The first three terms of a sequence are 1,7,8. If the average of the first four terms is 7 then the sum of the digits of the fourth term is
(a) 3
(b) 4
(c) 6
(d) 8
(e) 9
(a) 3
(b) 4
(c) 6
(d) 8
(e) 9
If the average of the first four terms is 7, and we know the first three digits, we can set up an equation:
(1+7+8+x)/4 = 7
Where x=the fourth value. Solving for x, we find that x=12.
So, the sum of its digits are 1+2=3.
