time and work Model Questions & Answers, Practice Test for ssc chsl tier 1 2023

Answer: (b)

Let the minimum time be t, when they meet at the starting point for the first time. So, the net distance covered must be a multiple of 11.

Now, (4 + 5.5 + 8) t = 11 (n)

where, n is an integer.

t = ${11(n)}/{17.5}$

minimum value of n is 35, so that we can get an appropriate value of time.

∴ t = ${11 × 35}/{17.5}$ = 22 hr.

Answer: (c)

1 man ≡ 2 boys ⇒(12 men + 18 boys)≡(12 × 2 + 18) boys = 42 boys.

Let required number of boys = x. 21 men + x boys ≡ (21 × 2 + x) boys = (42 + x) boys.

Less days, More boys (Indirect Proportion)

More hrs per day, Less boys (Indirect Proportion)

∴ [50 × 9 × 1 × (42 + x)] = $(60 × {15}/2 × 2 × 42)$

⇒(42 + x) =${37800}/{450}$⇒42 + x = 84⇒x = 42.

Answer: (a)

Let 1 man's 1 day's work = x and

1 boy's 1 day's work = y.

Then, 6x + 8y = $1/{10}$ and 26x + 48y = $1/2$.

Solving these two equations, we get :

x = $1/{100}$ and y = $1/{200}$

∴ (15 men + 20 boys)'s 1 day's work

= $({15}/{100} + {20}/{200}) = 1/4$

∴ 15 men and 20 boys can do the work in 4 days.

Answer: (a)

Work done together in one day = $1/8+1/10 = 9/{40}$

Therefore, the work will be completed together in ${40}/9$ or

4$4/9$ days.

Answer: (a)

Let the speed of the goods train be x kmph.

Distance covered by goods train in 10 hours

= Distance covered by express train in 4 hours.

∴ 10x = 4 × 90 or x = 36.

So, speed of goods train = 36 kmph.