Solved Questions from Postal Assistant Exam-2013

Tarun travels a distance of 24km at 6 km/hr another distance of 24km at 8 km/hr and a third distance of 24 km at 12 km/hr. His average speed for the whole journey (in km/hr) is
(A) 8 2/3
(B) 8
(C) 9
(D) 7
Ans. (B) 8

Solution:

 Time taken by Tarun to travel 24 km at 6 km/hr = 24/6 = 4 hrs.

Time taken by Tarun to travel 24 km at 8 km/hr = 24/8 = 3 hrs.

Time taken by Tarun to travel 24 km at 12 km/hr = 24/12 = 2 hrs.

 Avarage speed = Total Distance /Total Time = 24+24+24/4+3+2 = 72/9= 8hrs.

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 13 chairs and 5 tables were brought for 8280. If the average cost of the table will be 1227, what is the average cost of a chair?
(A) 2145
(B) 165
(C) 175
(D) None of these
Ans. (B) 165

Solution:

The total cost of 5 tables = 1227 x 5 =6135.

The cost of 13 chairs = 8280 – 6135 = 2145.

Therefore, the average cost of a chair = 2145/13 = 165.