Question: a and b can do a piece of work in 45 days and 40 days respectively . they began to do the work together but a leaves after some days and then b completed the remaining work in 23 days . the number of days after which a left the work was
A) 5 days
B) 6 days
C) 7 days
D) 9 days
E) 8 days
Correct answer: d
Grade: 6 | Topic: Ratios and proportions | Difficulty: Hard | Standard: 6.RP.A.3b