46.

A and B can together finish a work in 30 days. they worked at it for 20 days and then B left. the remaining work ws done by A alone in 20 more days. A alone can finish the work in :

 A. 48 Days B. 50 days C. 54 Days D. 60 days
Explanation:

47.

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. 12 B. 11 C. 10 D. 9
Explanation: (A+B)’s 1 day’s work =[ 1 45 + 1 40 ]= 17 360 ⇒ Work done by B in 23 days=1× 23 40 = 23 40 ⇒ Remaining work =1− 23 40 = 17 40 ⇒ Now, 17 360 work was done by (A+B) in 1 day. ⇒ 17 40 work was done by (A+B) in 1× 360 17 × 17 40 =9 days. Therefore, A left after 9 days.

48.

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. 12 B. 11 C. 10 D. 9
Explanation: (A+B)’s 1 day’s work =[ 1 45 + 1 40 ]= 17 360 ⇒ Work done by B in 23 days=1× 23 40 = 23 40 ⇒ Remaining work =1− 23 40 = 17 40 ⇒ Now, 17 360 work was done by (A+B) in 1 day. ⇒ 17 40 work was done by (A+B) in 1× 360 17 × 17 40 =9 days. Therefore, A left after 9 days.

49.

Two pipes can fill a tank in 20 and 24 minutes respectively and a waste pipe can empty 3 gallons per minute. All the three pipes working together can fill the tank in 15 minutes. The capacity of the tank in gallons is

 A. 100 B. 110 C. 120 D. 140