sheyla96
The average (arithmetic mean) of four different positive integers is 9. If the first of these integers in 3 times the second integer and the second integer is 2 less than the third integer, what is the least possible value of the fourth integer?
A) 5
B) 4
C) 3
D) 2
E) 1
We are given that the average of four different positive integers is 9. Thus, the sum of the integers is 4 x 9 = 36.
We can create the following equation in which a = the first integer, b = the second integer, c = the third integer, and d = the fourth integer:
a + b + c + d = 36
We are given that the first of these integers is 3 times the second integer. Thus:
a = 3b
We are also given that the second integer is 2 less than the third integer. Thus:
b = c - 2
b + 2 = c
We can substitute 3b for a and (b + 2) for c in the equation a + b + c + d = 36:
3b + b + b + 2 + d = 36
5b + d + 2 = 36
5b + d = 34
5b = 34 - d
b = (34 - d)/5
Since b is an integer, 34 - d must be a multiple of 5, and since the largest multiple of 5 less than 34 is 30, the smallest value for d is 4.
Answer: B