• ### If two thirds of a sum of money has been spent, leaving £24, how much money was there originally?

Best answer: If 2/3 rds spent , then you are left with '1/3'. 1/3 is equivalent £24. Multiply both sides by '3' 3(1/3) = £24 x 3 1 is equivalent £72 £72 is the original anount of money .
Best answer: If 2/3 rds spent , then you are left with '1/3'. 1/3 is equivalent £24. Multiply both sides by '3' 3(1/3) = £24 x 3 1 is equivalent £72 £72 is the original anount of money .
8 answers · Mathematics · 1 week ago
• ### Stuck on this maths question?

Best answer: BD^2 = (2sqrt(5))^2 - (3sqrt(2))^2 BD^2 = (4 x 5) - (9 x 2) BD^2 = 20 - 18 BD^2 = 2 BD = sqrt(2) Hence area = (1/2)(3sqrt(2) + sqrt(2))(sqrt(2) A = (1/2)(4sqrt(2)(sqrt(2)) A = (1/2)(4 x 2) A = 4 cm^2
Best answer: BD^2 = (2sqrt(5))^2 - (3sqrt(2))^2 BD^2 = (4 x 5) - (9 x 2) BD^2 = 20 - 18 BD^2 = 2 BD = sqrt(2) Hence area = (1/2)(3sqrt(2) + sqrt(2))(sqrt(2) A = (1/2)(4sqrt(2)(sqrt(2)) A = (1/2)(4 x 2) A = 4 cm^2
2 answers · Mathematics · 4 days ago
• ### Calculate Kc for the reaction?

Best answer: Initial moles = HI (1) H2 = 0 I2 = 0 Eqil moles = HI(0.2) H2 = 0.4 I2 = 0.4 NB The reaction has used 0.8 moles ( equivalent to '2' moles) to form 0.4 moles (equivalent to ''1') of each gas Hence Kc = [H2][I2] / [HI]^2 Kc = 0.4 x 0.4 / 0.2^2 Kc = 0.16 / 0.04 Kc = 4
Best answer: Initial moles = HI (1) H2 = 0 I2 = 0 Eqil moles = HI(0.2) H2 = 0.4 I2 = 0.4 NB The reaction has used 0.8 moles ( equivalent to '2' moles) to form 0.4 moles (equivalent to ''1') of each gas Hence Kc = [H2][I2] / [HI]^2 Kc = 0.4 x 0.4 / 0.2^2 Kc = 0.16 / 0.04 Kc = 4
3 answers · Chemistry · 1 month ago
• ### A circle passes through (3, -1) , (-2, 4) , and (6, 8)?

Best answer: x^2 + y^2 + 2fx + 2gy + c = 0 Hence 3^2 + (-1)^2 + 2f(3) + 2g(-1) + c = 0 9 + 1 + 6f - 2g + c = 0 10 + 6f - 2g + c = 0 (-2)^2 + 4^2 + 2f(-2) + 2g(4) + c = 0 4 + 16 - 4f + 8g + c = 0 20 - 4f + 8g + c = 0 6^2 + 8^2 + 2f(6) + 2g(8) + c = 0 36 + 64 + 12f + 16g + c = 0 100 + 12f + 16g + c = 0 Hence we have 10 + 6f - 2g + c =... show more
Best answer: x^2 + y^2 + 2fx + 2gy + c = 0 Hence 3^2 + (-1)^2 + 2f(3) + 2g(-1) + c = 0 9 + 1 + 6f - 2g + c = 0 10 + 6f - 2g + c = 0 (-2)^2 + 4^2 + 2f(-2) + 2g(4) + c = 0 4 + 16 - 4f + 8g + c = 0 20 - 4f + 8g + c = 0 6^2 + 8^2 + 2f(6) + 2g(8) + c = 0 36 + 64 + 12f + 16g + c = 0 100 + 12f + 16g + c = 0 Hence we have 10 + 6f - 2g + c = 0 20 - 4f + 8g + c = 0 100 +12f + 16g + c = 0 c = -10 - 6f + 2g Substitute 20 - 4f + 8g - 10 - 6f + 2g = 0 100 + 12f + 16g - 10 - 6f + 2g = 0 10 -10f +10g = 0 90 + 6f + 18g = 0 Factor f - g = 1 -f - 3g = 15 Add -4g = 16 g = -4 f - 4 = 1 f = 5 Hence x^2 + y^2 + 5x - 4y + c = 0 Substitute any point for 'c' 3^2 + (-1)^2 + 5(3) -4(-1) + c = 0 9 + 1 + 15 + 4 + c = 0 29 + c = 0 c = -29 Hence the equation becomes x^2 + y^2 + 5x - 4y - 29 = 0
3 answers · Mathematics · 6 days ago
• ### A length of copper wire has a mass of 3.77 g. How many moles of copper are in the wire?

Best answer: Remember the equation moles = mass / Ar NB Ar for Copper (Cu) = 63.5 moles = 3.77/ 63.5 = 0.059370....
Best answer: Remember the equation moles = mass / Ar NB Ar for Copper (Cu) = 63.5 moles = 3.77/ 63.5 = 0.059370....
2 answers · Chemistry · 1 week ago
• ### Fill in the geometric table and provide 6 statements along with 6 reasons that relate to the diagram shown.?

Best answer: 4 = 10 (Alternate angles 1 = 3 ( Vertically opposite 5 = 9 (Corresponding 3 + 10 = 180 (Allied angles 4 = 6 ( Alternate 6 = 10 (Corresponding 4 + 3 = 180 angles on a straight line 3 + 10 = 180 (Allied angles.
Best answer: 4 = 10 (Alternate angles 1 = 3 ( Vertically opposite 5 = 9 (Corresponding 3 + 10 = 180 (Allied angles 4 = 6 ( Alternate 6 = 10 (Corresponding 4 + 3 = 180 angles on a straight line 3 + 10 = 180 (Allied angles.
3 answers · Homework Help · 3 weeks ago
• ### AP Chemistry help (much needed)!?

Best answer: 2Cr(NO3)3 + Ca3(PO4)2 = 2CrPO4 + 3Ca(NO3)2 Chromiun nitrate. Calcium phosphate, Chromium phosphate & Calcium nitrate.
Best answer: 2Cr(NO3)3 + Ca3(PO4)2 = 2CrPO4 + 3Ca(NO3)2 Chromiun nitrate. Calcium phosphate, Chromium phosphate & Calcium nitrate.
3 answers · Chemistry · 2 weeks ago
• ### Which e3+ ion (where 3 is an element) is predicted to have a ground state electron configuration of [kr] 4d10 5s2 5p2?

1 answer · Chemistry · 4 weeks ago
• ### Find 100=3^x?

Best answer: Take logs to base 10 log 100 = x log 3 x = log 100 / log 3 x = 2 / 0.47712.... x = 4.1918.....
Best answer: Take logs to base 10 log 100 = x log 3 x = log 100 / log 3 x = 2 / 0.47712.... x = 4.1918.....
4 answers · Mathematics · 3 weeks ago
• ### Write a fraction that is between 0.1 and 1/5 has a whole number numerator and a denominator of 100 express this fraction in decimal form.?

Best answer: 0.1 = 1/10 = 10/100 1/5 = 20/100 So the numerator needs to be between 10 & 20 . so '15' is chosen 15/100 = 0.15 or 13/100 = 0.13
Best answer: 0.1 = 1/10 = 10/100 1/5 = 20/100 So the numerator needs to be between 10 & 20 . so '15' is chosen 15/100 = 0.15 or 13/100 = 0.13
5 answers · Mathematics · 1 month ago
• ### Find the length of rope is needed,the pole casts a shadow 12.6m long on the ground The angle of elevation is 38*40 . How tall is the pole?

Best answer: Trigonometry !!!! Known angle = 38.4 o Adjcaent (base) = 12.6 Opposite (height) to be found Trig function is Tangent Tan (x) = opposite / adjacent opposite = adjacent X Tan (x) Hence height = 12.6 X Tan (38.4) height = 12.6 x 0.792590233 height = 9.9866 m
Best answer: Trigonometry !!!! Known angle = 38.4 o Adjcaent (base) = 12.6 Opposite (height) to be found Trig function is Tangent Tan (x) = opposite / adjacent opposite = adjacent X Tan (x) Hence height = 12.6 X Tan (38.4) height = 12.6 x 0.792590233 height = 9.9866 m
7 answers · Mathematics · 1 month ago
• ### I need Help on a Statistic probability problem?

Best answer: The possibilities of a draw are PPP PPR PRP RPP There are no other possibilities for two Philips (P) screws. (PPP) ; P(3 P) = 4/11 x 3/10 x 2/9 = 4/165 (PPR) : P(2 P) = 4/11 x 3/10 x 7/9 = 14/165 (PRP) ; P(2 P) = 4/11 x 7/10 x 3/9 = 14/165 (RPP) ; P(2 P) = 7/11 x 4/10 x 3/9 = 14/165 4/165 +14/ 165 + 14/165 + 14/15 = 46/165 =... show more
Best answer: The possibilities of a draw are PPP PPR PRP RPP There are no other possibilities for two Philips (P) screws. (PPP) ; P(3 P) = 4/11 x 3/10 x 2/9 = 4/165 (PPR) : P(2 P) = 4/11 x 3/10 x 7/9 = 14/165 (PRP) ; P(2 P) = 4/11 x 7/10 x 3/9 = 14/165 (RPP) ; P(2 P) = 7/11 x 4/10 x 3/9 = 14/165 4/165 +14/ 165 + 14/165 + 14/15 = 46/165 = 0.27878.... NB Use a pictorial method. First draw is Philips or Regular out of 11 The second draw is out of 10 (No replacement) one screw already removed. Third draw is out of 9 ( No replacement) 2 screws already removed Hope that helps!!!!!
3 answers · Mathematics · 1 month ago
• ### What's a good name for a girl?

Best answer: Try Alexandra , Persephone Penelope Helen Cassandra Cassiopeia Thalia Are a few from Classical Greece.
Best answer: Try Alexandra , Persephone Penelope Helen Cassandra Cassiopeia Thalia Are a few from Classical Greece.
9 answers · Baby Names · 2 months ago
• ### How was the formula e=mc^2 former and how it exactly means?

Best answer: 'e = mc^2 'e' is energy 'm' is mass 'c' is the speed of light in a vacuum. It is very similar to Kinetic Energy KE = mv^2 KE = Kinetic Energy m = mass v = velocity /speed The ideas is a substance will loose mass to energy So if you have a 1 g pellet of say uranium When it undergoes nuclear fusion... show more
Best answer: 'e = mc^2 'e' is energy 'm' is mass 'c' is the speed of light in a vacuum. It is very similar to Kinetic Energy KE = mv^2 KE = Kinetic Energy m = mass v = velocity /speed The ideas is a substance will loose mass to energy So if you have a 1 g pellet of say uranium When it undergoes nuclear fusion it releases energy and the 1 g looses mass to say 0.999 g Hence Energy released is 1 - 0.999 = 0.001 e = 0.001( 3.0 x 10^8)^2 e = 0.001 x 9.0 x 10^(16) e = 9.0 x 10^(13) J (energy released). e = 9.0 x 10^(10) kJ These are hypothetical figures used to try and demonstrate, what is going on. However, you can see it releases an enormous amount of energy .
7 answers · Physics · 2 months ago
• ### HELP! Predict the equilibrium concentration of H+ in a 0.25 M solution of H2SO4-? Ka2=0.012?

Best answer: Ka = [H+]^2[SO4^2-] / [H2SO4] 0.012 = [H+]^2 [0,25] / [0.25] Hence [H+]^2 = 0.012 [H^+] = 0.10954451150103322269139395656016 [H+] = 0.1095 pH = -log(10)[0.1095] pH = -(-0.96) pH = 0.96
Best answer: Ka = [H+]^2[SO4^2-] / [H2SO4] 0.012 = [H+]^2 [0,25] / [0.25] Hence [H+]^2 = 0.012 [H^+] = 0.10954451150103322269139395656016 [H+] = 0.1095 pH = -log(10)[0.1095] pH = -(-0.96) pH = 0.96
2 answers · Chemistry · 6 months ago
• ### How is pH affected by an increase in H+ ions and by a decrease in H+ ions.?

Best answer: Increase in H^+ ; Decrease in numerical value of pH Decrease in H^+ ; In crease in numerical value of pH .
Best answer: Increase in H^+ ; Decrease in numerical value of pH Decrease in H^+ ; In crease in numerical value of pH .
3 answers · Chemistry · 2 months ago
• ### If you’re up to the task, what is 21 out of 42?

Best answer: '42' divided by '21' eqals '2' '42' subtract '21' equals '21'.
Best answer: '42' divided by '21' eqals '2' '42' subtract '21' equals '21'.
10 answers · Mathematics · 2 months ago
• ### What is the pressure in a 23.0-L cylinder filled with 44.1 g of oxygen gas at a temperature of 327 K?

Best answer: Use the Ideal Gas Equation PV = nRT P ; to be found V = 23.0 L = 0.023 m^3 n = moles O2 = 441./32 = 1.378125 moles R = the gas constant 8.314 T 327 K Substituting in P = nRT/V P = 1.378125 x 8.314 x 327 / 0.023 P = 162,899.049 Pa P = 1.607 atms.
Best answer: Use the Ideal Gas Equation PV = nRT P ; to be found V = 23.0 L = 0.023 m^3 n = moles O2 = 441./32 = 1.378125 moles R = the gas constant 8.314 T 327 K Substituting in P = nRT/V P = 1.378125 x 8.314 x 327 / 0.023 P = 162,899.049 Pa P = 1.607 atms.
2 answers · Chemistry · 2 months ago
• ### Chem Check????

Best answer: First write down the BALANCED reaction eq'n HCl + NaOH = NaCl + H2O Note the molar ratios are all 1:1::1:1 mol(HCl) = 0.02 x 2500 / 1000 = 0.05 moles ( equivalent to '1' in the molar ratios above). mol(NaOH) = 0.05 (Also equivalent to '1' in the molar ratios above) Hence 0.05 = 0.4 x vol(mL) / 1000 vol = 0.05... show more
Best answer: First write down the BALANCED reaction eq'n HCl + NaOH = NaCl + H2O Note the molar ratios are all 1:1::1:1 mol(HCl) = 0.02 x 2500 / 1000 = 0.05 moles ( equivalent to '1' in the molar ratios above). mol(NaOH) = 0.05 (Also equivalent to '1' in the molar ratios above) Hence 0.05 = 0.4 x vol(mL) / 1000 vol = 0.05 x 1000 / 0.4 vol = 125 mL is required.
2 answers · Chemistry · 2 months ago
• ### Popular baby names you hate?

Best answer: Any modern, misspelt, meaningless invention!!!! There are plenty of unused Classical & Biblical names, that are hardly ever used. They all have a meaning. e.g. Abigail (F) - God's hand maiden.
Best answer: Any modern, misspelt, meaningless invention!!!! There are plenty of unused Classical & Biblical names, that are hardly ever used. They all have a meaning. e.g. Abigail (F) - God's hand maiden.
19 answers · Baby Names · 1 year ago