Question: Calculate the largest 3 digit number which is exactly divisible by 89?
Options:
(A) 911
(B) 969
(C) 979
(D) 977
(E) 971
Answer: Largest 4 digit number is 999
After doing 999 ÷ 89 we get remainder 20
Hence largest 3 digit number exactly divisible by 89 = 999 - 20 = 979
The answer is (C).

Question: How long does a train 100 m long traveling at 72 kmph takes to cross a tunnel of 1400 m in length?
Options:
(A) 70 sec
(B) 60sec
(C) 82 sec
(D) 75 sec
(E) 62 sec
Answer: D = 1400+100 = 1500 m
S = 72 * 5/18 = 20
T = 1500 * 1/20 = 75 sec
The answer is (D).

Question: How many liters of oil at Rs.40 per liter should be mixed with 240 liters of a second variety of oil at Rs.60 per liter so as to get a mixture whose cost is Rs.52 per liter?
Options:
(A) 120
(B) 150
(C) 160
(D) 180
(E) 200
Answer: 8:12 = 2:3
If 240 lrs of the 2nd variety taken then the 1st variety should be taken as 160 lr
The answer is (C).

Question: A train 360 m long is running at a speed of 45 km/hr. In what time will it pass a bridge 140 m long?
Options:
(A) 40 sec
(B) 32 sec
(C) 12 sec
(D) 85 sec
(E) 56 sec
Answer:

Show your work and conclude with the exact phrasing "Therefore, the final answer is [answer]." where [answer] is just the final number or expression that solves the problem.
user
Answer: Option A
Speed = 45 * 5/18 = 25/2 m/sec
Total distance covered = 360 + 140 = 500 m
Required time = 500 * 2/25 = 40 sec
The answer is (A).