time and work Model Questions & Answers, Practice Test for ibps clerk prelims 2023

Answer: (a)

More men, less time (Indirect)

Let original number of men = x

$x/{x-5}$=${12}/{10}$

⇒10x =12x - 60

⇒2x = 60 ⇒ x = 30

Answer: (c)

In one hr. B finishes $1/{20}$ of the work.

In one hr. A finishes $1/{20} × 3/2 = 3/{40}$ of the work.

A+B finish ${2+3}/{40} = 1/8$ of the work in 1 hr.

Both of them will take 8 hrs. to finish the work.

Answer: (b)

Let the speed of the cars be x km/h and y km/h, respectively.

Their relative speed when they are moving in same direction = (x – y) km/h.

Their relative speed when they are in opposite directions = (x + y) km/h.

Now, ${70}/{x + y}$ = 1 or x + y = 70 ..... (i)

and ${70}/{(x - y)}$ = 7 or x – y = 10 ..... (ii)

Solving (i) and (ii), we have

x = 40 km/h and y = 30 km/h.

Answer: (b)

Suppose pipe A alone takes x hours to fill the tank.

Then, pipes B and C will take $x/2$ and $x/4$ hours respectively to fill the tank.

∴ $1/x + 2/x + 4/x = 1/5⇒7/x = 1/5$ ⇒ = 35 hrs.

Answer: (b)

Part filled in 7 min. = 7 × $(1/{36} + 1/{45}) = 7/{20}$

Remaining part = $ (1 - 7/{20}) = {13}/{20}$

Part filled by (A + B + C) in 1 min. = $(1/{36} + 1/{45} - 1/{30})$

=$1/{60}$.

$1/{60}$ Part is filled in 1 minute ${13}/{20}$ Part is filled in $({13}/{20} × 60)$ = 39 minutes