Question: one woman and one man can build a wall together in three hours , but the woman would need the help of two girls in order to complete the same job in the same amount of time . if one man and one girl worked together , it would take them five hours to build the wall . assuming that rates for men , women and girls remain constant , how many hours would it take one woman , one man , and one girl , working together , to build the wall ?
A) 5 / 2
B) 1
C) 10 / 7
D) 12 / 7
E) 22 / 7
Correct answer: a
Grade: 7 | Topic: Expressions and Equations | Difficulty: Hard | Standard: 7.EE.B.4a