Question

at a school number of boys : number of girls =9:7. There are 116 more boys than girls. Work out the total number of students at the school

Answer 1

Let x be a number of boys and y be a number of girls.
Then x:y=9:7, that is 7x=9y; and we have x-y=116.
Thus, x=116+y
7(116+y)=9y
7*116+7y=9y
2y=7*116
y=7*58=406
x=406+116=522
Total number of students is x+y=522+406=928.