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

Answer: (d)

(P+ Q + R)'s1 hour's work = $(1/8 + 1/{10} + 1/{12}) = {37}/{120}$

Work done by P, Q and R in 2 hours = $({37}/{120} × 2) = {37}/{60}$

Remaining work = $(1 - {37}/{60}) = {23}/{60}$

(Q + R)'s 1 hour's work = $(1/{10} + 1/{12}) = {11}/{60}$

Now, ${11}/{60}$ work is done by Q and R in 1 hour..

So, ${23}/{60}$ work will be done by Q and R in

$({60}/{11} × {23}/{60}) = {23}/{11}$ hours ≈ 2 hours.

So, the work will be finished approximately 2 hours after 11 a.m., i.e., around 1 p.m.

Answer: (a)

Let the remaining food will last for x days.

500 men had provision for (27 – 3) = 24 days.

(500 + 300) men had provisions for x days.

More men, Less days (Indirect Proportion)

∴ 800 : 500 :: 24 : x = (800 × x) = (500 × 24)

⇒x = ${500 × 24}/{800}$ = 15

Answer: (c)

Let the total distance be x km. Then,

${1/2 x}/{21} + {1/2 x}/{24} = 10⇒x/{21} + x/{24}$ = 20

⇒15x = 168 × 20⇒ x = $({168 × 20}/{15})$ = 224 km.

Answer: (d)

Let required number of binders be 'x'

Less books, less binders (direct)

More days, less binders (indirect)

900 × 12 × x = 660 × 10 × 18

x=${660×10×18}/{900×12}$=11

Answer: (c)

Part of tank filled in 1 hour = 1/3

Part of tank emptied in the same time = $1/3 - 1/{3.5}$

Total time required to empty it = $1/{1/3 - 1/{3.5}}$ = 21 hours