A manufacturer produces a certain men's athletic shoe in integer sizes from 8 to 17. For this particular shoe, each unit increase in size corresponds to a 1/5-inch increase in the length of the shoe. If the largest size of this shoe is 40% longer than the smallest size, how long, in inches, is the shoe in size 15? Choices:
A) 5.4
B) 5.9
C) 6.3
D) 6.7
E) 7.5

Rationale: let x be the length of the size 8 shoe . then 0.4 x = 9 / 5 x = 4.5 inches the size 15 shoe has a length of 4.5 + 7 / 5 = 5.9 inches the answer is b .
Answer: B