Rationale: Speed = 36 * 5/18 = 10 m/sec
Total distance covered = 360 + 140 = 500 m
Required time = 500 * 1/10 = 50 sec
The answer: (B)
Question: A train 360 m long is running at a speed of 36 km/hr. In what time will it pass a bridge 140 m long?
Options:
(A) 40 sec
(B) 50 sec
(C) 88 sec
(D) 19 sec
(E) 10 sec
Reasoning: Work done by X in 1 day = 1/18
Work done by Y in 1 day = 1/15
Work done by Y in 10 days = 10/15 = 2/3
Remaining work = 1 2/3 = 1/3
Number of days in which X can finish the remaining work = (1/3) / (1/18) = 6
Ans: (C)
Question: X can finish a work in 18 days. Y can finish the same work in 15 days. Yworked for 10 days and left the job. how many days does X alone need to finish the remaining work?
Options:
(A) 3
(B) 5
(C) 6
(D) 7
(E) 9
Rationale: 2nd day he earns = 3(2 5)
3rd day he earns = 3(3 5)
On 20th day he earns 3(20 -5) = 45 rupees
The answer: (D)
Question: An enterprising businessman earns an income of Re 5 on the first day of his business. On every subsequent day, he earns an income which is just thrice of that made on the previous day. On the 10th day of business, he earns an income of:
Options:
(A) 21
(B) 22
(C) 20
(D) 45
(E) 30
Reasoning: The total distance D traveled by John is given by
D = 45 * 2 + 3 * 50 = 240 miles.
Ans: (C)
Question: John left home and drove at the rate of 45 mph for 2 hours. He stopped for lunch then drove for another 3 hours at the rate of 50 mph to reach his destination. How many miles did John drive?
Options:
(A) 235 miles.
(B) 245 miles.
(C) 240 miles.
(D) 265 miles.
(E) 275 miles.
Rationale: D = 72 * 5/18 = 20 = 400 250 = 150m
The answer: (A)
Question: A train 250 m long running at 72 kmph crosses a platform in 20 sec. What is the length of the platform?
Options:
(A) 150m
(B) 200m
(C) 250m
(D) 270m
(E) 300 m
Rationale: 1/30 + 1/40 = 7/120
120/7 = 17 1/7 days
The answer: (A)
Question: Ravi can do a piece of work in 30 days while Prakash can do it in 40 days. In how many days will they finish it together?
Options:
(A) 17 1/7 days
(B) 27 1/7 days
(C) 23 2/7 days
(D) 16 4/11 days
(E) none of these