Three taps P, Q and R can fill a tank in 12 hrs, 15 hrs and 20 hrs respectively. If P is open all the time and Q and R are open for one hour each alternately, starting with Q, then the tank will be full in how many hours ?

Correct Answer: Rs.70

Explanation:

Efficiency of kaushalya = 5%

Efficiency of kaikeyi  = 4%

Thus, in 10 days working together they will complete only 90% of the work.

          [(5+4)*10] =90

Hence, the remaining work will surely done by sumitra, which is 10%.

Thus, sumitra will get 10% of Rs. 700, which is Rs.70

Correct Answer: 10 days

Explanation:

Ratio of efficiencies of Priya and Sai is

Sai : Priya = 160 : 100 = 8 : 5

Given Priya completes the work in 16 days

Let number of days Sai completes the work be 'd'

=> 5×16 = 8×d

d = 10 days.

Therefore, number of days Sai completes the work is 10 days.

Correct Answer: 100

Explanation:

Let the Efficiency of pavan be E(P)

Let the Efficiency of sravan be E(S)

Here Work W = LCM(25,20) = 100

Now, E(P+2S) = 100/25 = 4 ....(1)

E(2P+S) = 100/20 = 5 ....(2)

Hence, from (1) & (2) we get

E(S) = 1

=> Number of days Savan alone work to complete the work  = 100/1 = 100 days.

Correct Answer: 26 2/3 days

Explanation:

1/3 ---- 8

1 -------?
Hari can do total work in = 24 days

As satya is 60% efficient as Hari, then

Satya = 1/24 x 60/100 = 1/40

=> Satya can do total work in 40 days

1 ----- 40

2/3 ---- ? => 26 2/3 days.

Correct Answer: 4 days

Explanation:

One day work of 6 boys and 8 girls is given as 6b + 8g = 1/10 -------->(I)

 

One day work of 26 boys and 48 women is given as 26b + 48w = 1/2 -------->(II)

 

Divide both sides by 2 in (I) and then multiply both sides by 5

Now we get, 15b + 20g = 1/4.

Therefore, 15 boys and 20 girls can do the same work in 4 days.

Correct Answer: 3 pm

Explanation:

Work done by P and Q in the first two hours, working alternately

= First hour P + Second hour Q

? 1 4 + 1 12 = 1 3

work is completed in 2 hours

Then, the total time required to complete the work by P and Q working alternately=2 x 3= 6hours

Thus, work will be completed at 3pm.

Correct Answer: 48/5 days

Explanation:

Amount of work K can do in 1 day = 1/16

Amount of work L can do in 1 day = 1/12

Amount of work K, L and M can together do in 1 day = 1/4

Amount of work M can do in 1 day = 1/4 - (1/16 + 1/12) = 3/16 ? 1/12 = 5/48

=> Hence M can do the job on 48/5 days = 9 (3/5) days  

Correct Answer: 36 days

Explanation:

Given the ratio of efficiencies of P, Q & R are 3 : 8 : 5

Let the efficiencies of P, Q & R be 3x, 8x and 5x respectively

They can do work for 12 days.

=> Total work = 12 x 16x = 192x

 

Now, the required time taken by Q to complete the job alone = 162 x 8 x = 24days.

Correct Answer: 2

Explanation:

Let workdone 1 boy in 1 day be b

and that of 1 girl be g

From the given data,

4(5b + 3g) = 23

20b + 12g = 23 .......(a)

 

2(3b + 2g) = 7

6b + 4g = 7 ........(b)

 

Solving (a) & (b), we get

b = 1, g = 1/4

 

Let number og girls required be 'p'

6(7 x 1 + p x 1/4) = 45

=> p = 2.

 

Hence, number of girls required = 2

Correct Answer: 20 hrs

Explanation:

Time taken by both Meghana and Ganesh to work together is given by =

t 1 x t 2

Where

$$\begin{gathered} t 1 = 32 h r s \\ t 2 = 12 1 2 h r s = 25 2 h r s \end{gathered}$$

 

Therefore, time took by both to work together = 

32 x 25 2 = 16 x 25 = 4 x 5 = 20 h r s