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.

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

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.