There are 352 students who are enrolled in an introductory engineering course. If there are seven boys to every nine girls, how many boys are in the course?
Let
x------> number of boys
y -----> number of girls
we have that
x+y=352 --------> y=352-x ------> equation A
x/y=7/9
x=(7/9)y -------> equation B
substitute equation A in equation B
x=(7/9)(352-x)
9x=2,464-7x
9x+7x=2,464
16x=2,464
x=154
therefore
the answer is
154 boys