8 problems = 20 min
8/20 problems = 20/20 min
0.4 problems = 1 min
The unit rate is 0.4 problems per minute
x = number of minutes
(unit rate)*(number of minutes) = amount done
0.4x = 30
x = 30/0.4
x = 75
You'll need 75 minutes to do 30 problems assuming you can keep the same rate going.
Side note:
75 min = 60 min + 15 min = 1 hour + 15 min
or
75 min = 1 hour + 15 min = 1 hour + (15/60) hour = 1 hour + 0.25 hour = 1.25 hours
Hi
If you can complete 8 math problems in 20 minutes.
How long should it take to do thirty math problems?
Cross Multiply to Solve:
8x = 600
x = 75min
Wish You the Best in your Studies.