Answer:
69.75 miles
Step-by-step explanation:
Akim runs 1.75 miles on his first day of training.
He increases his distance run by 0.25 miles the day after that i.e.
He runs 1.75+0.25 miles
On third day again he increases his distance by 0.25 miles i.e.
He runs 1.75+0.25+0.25 miles
i.e. on nth day he runs 1.75+0.25(n-1)
Total number of miles Akim runs over the course of 18 days is:

=69.75 miles