C. 90
5 : 3 = 150 : 90
[tex] \frac{5}{3} = \frac{150}{90} [/tex]
Cross multiply to check:
[tex] \: \: 5(90) = 3(150) \\ 450 = 450[/tex]
You will also notice that both 5 and 3 are multiplied by 30 to get the equivalent ratio of 150 and 90.
I just divided 150 and 5 since the boys in the ratio have their given number. Not sure how to explain it. Hope you get it.
