Based on the given information, you can write the following equations for the costs:
y1 = 35x + 75
y2 = 38x
If the cost is the same for both companies, you have:
35x + 75 = 38x
you can solve the previous equation for x to determine the number of people:
35x + 75 = 38x subtract 35x both sides
75 = 38x - 35x
75 = 3x divide by 3 both sides
75/3 = x
25 = x
Hence, the number of people is 25
