time and work Model Questions & Answers, Practice Test for rbi grade b prelims 2024

Answer: (a)

10 women × 12 = 5 men × 8

1 man = ${120}/{40}$ women = 3 women

Now

6 women + 3 men = 6 women + 3 × 3 women = 15 women

∴ 15 women × No. of days = 10 women × 12 days

∴ Required no. of days = ${10 women × 12 days}/{15 women}$

= 8 days

Answer: (b)

Let pipes A, B, C fill a tank in x, y and z hrs. respectively.

Then x = 60 min, y = 75 min, z = z min

Required time to fill the tank = 50 min.

But Required time = ${xyz}/{yz + zx - xy}$

50 = ${60 × 75 × z}/{75z + 60z - 60 × 75}$

⇒5 = ${450z}/{135z - 4500}$

⇒5(135z – 4500) = 450z

⇒675z – 4500 × 5 = 450 z

⇒675z – 450z = 4500 × 5

⇒z = ${4500 × 5}/{225}$ = 100

∴ Option (a) is correct.

Answer: (d)

(Mother + Daughter)'s one day's work = $1/4$

Remaining work = $3/4$

Mother's one day's work = $1/6$

Daughter's one day's work = $1/4-1/6 = 1/{12}$

$1/{12}$ work is done by the daughter in 1 day.

Therefore, $3/4$ work will be done by the daughter in

${12 × 3}/4$ = 9 days

Answer: (a)

Let the required number of days be x.

Less persons, More days (Indirect Proportion)

More working hrs per day, Less days (Indirect Proportion)

∴ 30 × 6 × x = 39 × 5 × 12⇔x = ${39 × 5 × 12}/{30 × 6}$⇔x = 13.

Answer: (d)

∵ ${M_1D_1}/{W_1} = {M_2D_2}/{W_2}⇒{5 × 1/2}/{1/{48}} = {6 × D_2}/{1/{40}}$

⇒$D_1 = {1/2 × 5 × 48}/{40 × 6} = 1/2$