Answer:
32.5 miles on the 7th day
Explanation:
1, 1.5, 2.5, 4.5
We need to determine the pattern
We are adding .5 + 1/4(2^n)
Lets check
n=1 .5+ 1/4(2) = .5+ .5 =1
n =2 .5 + 1/4*2^2 = .5 +1 = 1.5
n=3 .5 + 1/4 ( 2^3) = .5 + 8/4 = 2.5
n=4 .5 + 1/4 (2^4) = .5 + 16/4 = 4.5
n = 5 .5 + 1/4 (2^5) = .5 +32/4 = 8.5
n = 6 .5 + 1/4 (2^6) = .5 + 64/4 =16.5
n=7 .5 + 1/4(2^7)= .5 + 1/4(128) = 32.5
They bike 32.5 miles