There is enough provisions for 600 men in an army camp for 25 days. If there were 100 men less, how long will the provision last?  Options:
A) 10 days B) 50 days C) 100 days D) 150 days E) 200 days

Rationale: "exp : we have , m 1 d 1 = m 2 d 2 600 * 25 = 100 * d 2 d 2 = 600 * 25 / 100 = 150 days . answer : d"
Answer: D