Final answer:
Jack spent 8 3/4 hours on his homework last week. This was calculated by converting Jill's time spent into an improper fraction and then multiplying it by 1 2/5 to find Jack's total time spent.
Step-by-step explanation:
The student is asking how long Jack spent doing his homework if he spends 1 2/5 times as long on his homework as Jill, who spent 6 1/4 hours doing homework last week. To find the time Jack spent, we can convert Jill's hours into an improper fraction and then multiply by 1 2/5.
Jill's time in hours: 6 1/4 = 6*4/4 + 1/4 = 24/4 + 1/4 = 25/4 hours
Since 1 2/5 is equal to 7/5, we multiply Jill's time by 7/5 to find Jack's time:
Jack's time in hours: (25/4) * (7/5) = (5*5*7)/(4*5) = 35/4 = 8 3/4 hours
So, Jack spent 8 3/4 hours on his homework last week.