AFCAT Model Paper 4

Given: The quantity of alcohol in a 27 quartz capacity car radiator = 18% Drained and Replace quantity = 90% alcohol solution The resulting solution contains 90% alcohol Calculation: According to the question We have to mix 18% alcohol solution with 90% alcohol solution to get a 42% alcohol solution. Let’s assume that x quartz of 18% solution are mixed with y quartz of 90% solution. Amount of alcohol in x quartz of 18% solution = 0.18x Quartz Amount of alcohol in y quartz of 90% solution = 0.90y Quartz Total amount of alcohol in x + y quartz = 0.18x + 0.9y ⇒ 0.42 (x + y) = 0.18x + 0.9y ⇒ 0.24x = 0.48y ⇒ x : y = 2 : 1 We know that, x + y = 27 ⇒ x = 18 and y = 9 ∴ 9 quartz of 18% solutions are drained and replaced with 90% solution.