If 6a = 7b = 20, then 84ab = Pick one:
A) 50
B) 100
C) 625
D) 800
E) 1250

Rationale: "6 a * 7 b = 20 * 20 = 400 42 ab = 400 i . e . 84 ab = 800 answer : option d"
Answer: D