A cement mixture is composed of 3 elements. By weight, 1/3 of the mixture is sand, 1/4 of the mixture is water, and the remaining 10 pounds of the mixture is gravel. What is the weight of the entire mixture in pounds?
Choices.
A) 24 B) 26 C) 28 D) 30 E) 36

Rationale: "let the total weight be x . sand content = ( 1 / 3 ) x water content = ( 1 / 4 ) x gravel = x - ( 1 / 3 ) x - ( 1 / 4 ) x = ( 5 / 12 ) x = 10 x = 24 then answer will be a = 24"
Answer: A