2. Jack ran 5 miles in 42.5 minutes. Jill ran 3 miles in 23.25 minutes. Who ran faster? How do you know?

Jill ran faster. I know because I compared both of their unit rates.

Jack's unit rate is 5/42.5 = 0.118 mile per minute (rounded)

Jill's unit rate is 3/23.25 = 0.129 mile per minute (rounded)

Jill runs a greater part of a mile per minute than Jack does.

She is faster. There's no getting around it.

Jack: 42.5 : 5 = 8.5

Which means Jack runs 1 mile in 8.5 minutes

jill: 23.25 : 3 = 7.75

Which means Jill runs 1 mile in 7.75 minutes

Jill is faster