A computer solved several problems in succession. The time it took the computer to solve each successive problem was the same number of times smaller than the time it took for the preceding problem. How many problems were suggested ti the computer if it spent 63.5 minutes to solve all the problems except the first, 127 minutes to solve all problems except for the last one and 31.5 minuter to solve all problems except for the first two?
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1 Answers
135763.5+a=127+arn-1=31.5+a+ar
from first and third ar=32
from first and second
a-arn-1=63.5=64-1/2
32/r-32rn-2=64-1/2
1/r-rn-2=2-1/64
r=1/2 and n-2=6
n=8
