Answer: 10 hours
Step-by-step explanation:
Given
Slow fix auto charge $28 for parts and $48 per hour of labor
We work charge $59 for parts and $44.90 per hour of labor
Suppose both works for x hours
Cost of Slow fix= 
Cost of We work= 
When these costs are the same

Let us say that:
K = age of Kristen
B = age of Ben
From the problem, we make the equations:
eqtn 1: K + B = 32
eqtn 2: (K – 4) = 2 (B – 4)
Simplifying eqtn 2:
K – 4 = 2 B – 8
K = 2 B – 4
Plugging in this to eqtn 2:
(2 B – 4) + B = 32
3 B – 4 = 32
3 B = 36
B = 12
From eqtn 2:
K = 2 B – 4 = 2 (12) – 4 = 20
So Kristen is 20 while Ben is 12.
The consecutive integers are i, i+1, i+2, i+3.
3 less than sum of the integers
= i + i +1 + i + 2 + i + 3 - 3 = 4i + 3
Answer: I believe you are correct I got the same answer as you.