Question

On average, Debbie can finish 4 algebra problem in 30 minutes. If Debbie works at this rate, how many problems will she solve in 2.5 hours? Justify your answer.

Answer 1

She will solve 20 problems in 2.5 hours, 4*5 thirty minute sessions=20.

Answer 2

If 4 = 30, that means 8 = 60 (which is one hour)

that means if 8 = 60, 16 = 120, 

If 120 is 2 hours, we need to add another 30 minutes. 
30 minutes is 4 algebra questions so our answer would be 20 = 150 minutes
150 minutes = 2.5 hours.