Question
You are training for a marathon. Currently, you can run 12 miles. You increase the distance you run on your long-run day by 7/10 mile each week. In how many more weeks will you be able to run 26 miles?
Answers
Reiny
Your running distances are in an arithmetic sequence with
a = 12 , d = 7/10 or .7
you want
a + (n-1)d = 26
12 + .7(n-1) = 26
.7n - .7 = 14
.7n = 14.7
n = 21
So it will take 20 MORE weeks to reach 26 miles
a = 12 , d = 7/10 or .7
you want
a + (n-1)d = 26
12 + .7(n-1) = 26
.7n - .7 = 14
.7n = 14.7
n = 21
So it will take 20 MORE weeks to reach 26 miles