Question: a and b together can do a work in 3 days . a alone can do it in 12 days . what time b will take to do the work alone ?
A) 4 days
B) 8 days
C) 12 days
D) 10 days
E) 5 days
Correct answer: a
Grade: 7 | Topic: Ratios and proportions | Difficulty: Easy | Standard: 7.RP.A.3