Sequence Question GMAT, GRE

A worker is hired for 7 days. Each day, he is paid 10 dollars more than what he is paid for the preceding day of work. The total amount he was paid in the first 4 days of work equaled the total amount he was paid in the last 3 days. What was his starting pay?

(A) 90
(B) 138
(C) 153
(D) 160
(E) 163





Start by eliminating C, B and E as the last digits have to be equal.

Try letter B) 
138, 148, 158, 168... 8*4 = 32 
Is not equal to 178, 188, 198 = 8*3 = 24

Trying A, 420 = 420.

90 + 100 + 110 + 120 = 130 + 140 +150

A