Answer:
First set = 60 minutes
Second set = 66 minutes
Step-by-step explanation:
Given that:
Length of third set = 71.28 minutes ;
Third set was 8% longer than second set ;
Length of second set = x
Third set = (100% + 8%) = 108% of second set
71.28 = 1.08 * x
71.28 = 1.08x
x = 71.28 / 1.08
x = 66
Hence, second set = 66 minutes
Second set was 10% longer than the first
(100 + 10)% of first set = second set
110% of first set = second set
Let first set = y
1.1 * y = 66
1.1y = 66
y = 66 / 1.1
y = 60
Hence, first set = 60 minutes
First set = 60 minutes
Second set = 66 minutes