We are given the following inequality

Let us solve the inequality for a.
Flip the fractions (the signs will be reversed)

Multiply the inequality by 5

So a must be greater than 75/7 (that is 10.71) next integer is 11 (rounding up)
a must be less than 80/3 (that is 26.67) previous integer is 26 (rounding down)
So, the values of a that satisfy the inequality are
11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26
These are a total of 16 values
Therefore, 16 different values of a satisfy this inequality.