math
posted by Anonymous .
in 4a and 4c there are same no of girls total there are 56 people in both the classes if 1/3 of people in 4a and 1/4th of people in 4c are girls find total number of girls in both the classes

I'm going to rewrite the question to make sure I've understood it. In 4a and 4c there are the same number of girls. There are 56 pupils in total in the two classes. If 1/3 of the people in 4a and 1/4 of the people in 4c are girls, find the total number of girls in both classes. Yes? If so, then suppose there are G girls in each class (because we know the number is the same in each). The number of pupils in 4a must be 3G (because onethird of them are girls), and the number of pupils in 4c must be 4G (because onequarter of them are girls). So the total number of pupils in 4a AND 4c must be 3G + 4G = 7G. But we know that's 56  so G must be 8. (Note that 56 is exactly divisible by 7, so that's a good sign we're probably on the right track). So... if G is 8 girls in each class, then there must be 16 girls in total. Check it: Class 4a has 8 girls and 16 boys = 24 pupils, and class 4c has 8 girls and 24 boys = 32 pupils. Total number of pupils is 24 + 32 = 56, which looks good to me.