Answer:
43
Explanation:
Use the mean formula:
mean = (sum of elements) / (number of elements)
Let x represent the fourth number, and solve for x:
mean = (sum of elements) / (number of elements)
40 = (35 + 41 + 41 + x) / 4
40 = (117 + x) / 4
160 = 117 + x
43 = x
So, the fourth number is 43