Jack spends 1 3/4 as long on his homework as jill. last week jill spent 6 1/2 hours on her homework. how long did jack spend doing his homework? the week before jack spent 19 1/2 hours doing his homework. how long did jill spend on doing homework?

X = jacky = jill

x = 1 3/4y
y = 6 1/2

x = 1 3/4(6 1/2)
x = 7/4 * 13/2
x = 91/8 = 11 3/8 hrs <=== jack spent on homework

x = 1 3/4y
x = 19 1/2

19 1/2 = 1 3/4y
(19 1/2) / (1 3/4) = y
(39/2) / (7/4) = y
39/2 * 4/7 = y
78/7 = y
11 1/7 = y <===jill spent doing homework

The answer to your question is d 68%