Aptitude Solved Problems

Aptitude Solved Problems
1. The length of the bridge, which a train 130 metres long and travelling at 45 km/hr can cross in 30 seconds, is?

Answer: 245 metre.

Explanation:

Speed = 45 km/hr
To convert km/hr to m/sec multiply it with ( 5/ 18 )
Speed = 45 * ( 5 / 18 )
Speed = ( 25 / 2 ) m/sec
Time = 30 sec.
Let the length of bridge be x metres.
Then, ( 130 + x ) / 30 = ( 25 / 2 )
⇒2 ( 130 + x ) = 750
260 + 2x = 750
2x = ( 750 - 260 )
2 x = 490
x = 245 m

∴ The length of bridge is 245 metre.


2. The average age of husband, wife and their child 3 years ago was 27 years and that of wife and the child 5 years ago was 20 years. The present age of the husband is

Answer: 40 years.

Explanation:

Sum of the present ages of husband, wife and child is
= (27 * 3 + 3 * 3) years
= 90 years. Sum of the present ages of wife and child is
= (20 * 2 + 5 * 2) years
= 50 years. Husband′s present age = (90 - 50) years
= 40 years

∴ The present age of the husband is 40 years.


3. Sriram started a software business by investing Rs. 50,000. After six months, Nandini joined her with a capital of Rs. 80,000. After 3 years, they earned a profit of Rs. 24,500. What was Sriram′s share in the profit?

Answer: Rs. 10500.

Explanation:

Sriram : Nandini = (50000 * 36) : (80000 * 30)
= 1800000 : 2400000
= 1800 : 2400
= 3 : 4.
Sriram′s share = Rs. 24500 * ( 3 / 7 )
= ( 73500 / 7 )
= Rs. 10500.

∴ Sriram′s share in the profit is Rs. 10500.


4. When tossing two coins once, what is the probability of heads on both the coins?

Answer: ( 1 / 4 ).

Explanation:

Total number of outcomes possible when a coin is tossed = 2
Hence, total number of outcomes possible when two coins are tossed, n(S) = ( 2 * 2 ) = 4
E = event of getting heads on both the coins = {HH}
Hence, n(E) = 1
P (E) = n (E) / n (S)
P (E) = ( 1 / 4 )

∴ The probability is ( 1 / 4 ).