Driving Through The Country
Algebra
Level
3
I decided to drive through the country leisurely and on the first day I did only 7 miles. On the last day I did 51 miles, increasing my journey 4 miles each day.
How many days did I travel?
The answer is 12.
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1 solution
a(n) = a(1) + d*(n-1)
a(1) = 7
a(n) = 51
d = 4
51 = 7 + 4 (n-1) = 7 + 4 n - 4 = 3+ 4*n
48 = 4*n so n = 12