In a certain brick wall, each row of bricks above the bottom row contains one less brick than the row just below it. If there are 5 rows in all and a total of 50 bricks in the wall, how many bricks does the bottom row contain ? Choose the most appropriate option: A) 12 B) 10 C) 9 D) 8 E) 11

Rationale: the bottom row has x bricks x + x - 1 + x - 2 + x - 3 + x - 4 = 50 5 x - 10 = 50 5 x = 40 x = 8 answer : d
Answer: D