Question 664911
Each day he runs {{{2^(x-1)}}} miles. where x equal 1 on Monday, 2 on tuesday, 3 on wed etc
Monday 1
Tuesday 2^1 = 2
Wed 2^2 = 4
Thur 2^3 = 8
Fri 2^4 = 16

Total is 31 miles or {{{(2^(x-1)) - 1}}} where x = 5