Aptitude Solved Problems

Aptitude Solved Problems

Bright Zoom Maths,

1. 36 men can complete a piece of work in 18 days. In how many days will 24 men complete the same work?

Answer: 

27 days

Explanation:

Let the required number of days be x.
⇒ Less men, More days ( ∴ Indirect propportion )
⇒ 24 : 36 :: 18 : x
⇒ 24x = 36 * 18
x = ( 36 * 18 ) / 24
x = 9 * 3
x = 27 days

∴ 27 days to complete the work


2. In a lottery, there are 25 prizes and 10 blanks. A lottery is drawn at random. What is the probability of getting a prize?

Answer:

 5 / 7

Explanation:

Total number of outcomes possible, n ( S ) = 25 + 10 = 35
Total number of prize, n ( E ) = 25
p ( E ) = n ( E ) / n ( S )
= 25 / 35. = 5 / 7

∴ Required probability = 5 / 7

3. Three numbers are in the ratio of 2 : 3 : 4 and their L.C.M. is 360. Find their H.C.F. ?

Answer: 

30

Explanation:

Let HCF of the numbers be x
Let the numbers be 2x, 3x and 4x.
LCM of 2x, 3x and 4x = 12x
⇒ 12x = 360
x = 360 / 12
x = 30

∴ H.C.F of 2x, 3x and 4x = 30


4. A and B together can complete a piece of work in 4 days. If A alone can complete the same work in 12 days, in how many days can B alone complete that work?

Answer: 

6 days

Explanation:

( A + B )′s 1 day′s work = 1 / 4
A′s 1 day′s work = 1 / 12
B′s 1 day′s work = [ ( 1 / 4 ) - ( 1 / 12 ) ]
= ( 3 - 1 ) / 12
= 2 / 12
= 1 / 6

∴ Hence B alone can complete the work in 6 days.