Question

Jack spends 1 and 4/5 as long on his homework as Jill. Last week Jill spent 9 and 3/4 hours doing homework. How long did Jack spend doing homework?

The week before Jack spend 18.5 hours doing homework, how long did Jill spend doing homework?

Answer 1

x = jack
y = jill

x = 1 4/5y
y = 9 3/4

1 4/5(9 3/4)
x = 9/5 * 39/4
x = 351/20
x = 17 11/20 hrs <== time Jack spent doing homework

x = 1 4/5y
y = x / (1 4/5)
y = (18.5) / (9/5)
y = 18.5 * 5/9
y = 92.5/9
y = 10.28 <== Jill's time doing homework