Question

In David's class, 3/5 of the boys build model rockets to launch. Instead of parachutes,streamers were used on 2/9 of the Rockets, to slow them down. What fraction of the boys build rockets that had streamers?

Answer 1

so 3/5 of boys had rockets
2/9 of (boys that had rockets) had streamers
3/5=boys that had rockets
subsitue
2/9 of 3/5
'of' means multiply
2/9 times 3/5
remember that a/b times c/d=(ac)/(bd) so
2/9 times 3/5=(2 times 3)/(9 times 5)=6/45=2/15

so 2/15 of the boys had streamers