CAT Quantitative Aptitude Questions | CAT Ratios, Mixtures, Alligations and Averages Questions

The question is from CAT Ratio, Mixtures and Averages. Ratio of two mixtures are given and we need to relate one mixture with other and compare the variables from them. CAT exam is known to test on basics rather than high funda ideas. A range of CAT questions can be asked from Ratios and Proportions, Mixtures, Alligations and Averages. Make sure you master the topics. 2IIMs CAT questions bank provides you with CAT questions that can help you gear for CAT Exam CAT 2023.

Question 20: In class A, the ratio of boys to girls is 2 : 3. In class B the ratio of boys to girls is 4 : 5. If the ratio of boys to girls in both classes put together is 3 : 4, what is the ratio of number of girls in class A to number of girls in class B?

Explanatory Answer

Method of solving this CAT Question from Ratio, Mixtures and Averages: When we mix two mixtures in a particular ratio, we get a third mixture. Given the third mixture how does one find the ratio in which they were mixed.

Let us assume class A has 2x boys and 3x girls, class B has 4y boys and 5y girls.
\\frac{2x + 4y}{3x + 5y}\\) = \\frac{3}{4}\\)
8x + 16y = 9x + 15y
x = y
Required ratio = \\frac{3x}{5y}\\) (since x = y) = \\frac{3}{5}\\)

The question is "what is the ratio of number of girls in class A to number of girls in class B?"

Hence, the answer is "\\frac{3}{5}\\)".