2
Q:

# A and B together finish a wor in 20 days.They worked together for 15 days and then B left. Afer another 10 days,A finished the remaining work. In how many days A alone  can finish the job?

 A) 30 B) 40 C) 50 D) 60

Explanation:

(A+B)'s 15 days work=$\inline&space;{\color{Blue}&space;(\frac{1}{20}\times&space;15)=\frac{3}{4}}$

Remaining work =$\inline&space;{\color{Blue}&space;(1-\frac{3}{4})=\frac{1}{4}}$

Now, $\inline&space;{\color{Blue}&space;\frac{1}{4}}$ work is done by A in 10 days.

Whole work will bedone by A in $\inline&space;{\color{Blue}&space;(10\times&space;4)=40}$ days.

Q:

A,B,C together can do a piece of work in 10 days.All the three started workingat it together and after 4 days,A left.Then,B and C together completed the work in 10 more days.In how many days can complete a work alone ?

 A) 25 B) 24 C) 23 D) 21

Explanation:

(A+B+C) do 1 work in 10 days.
So (A+B+C)'s 1 day work=1/10 and as they work together for 4 days so workdone by them in 4 days=4/10=2/5
Remaining work=1-2/5=3/5
(B+C) take 10 more days to complete 3/5 work.
So( B+C)'s 1 day work=3/50
Now A'S 1 day work=(A+B+C)'s 1 day work-(B+C)'s 1 day work=1/10-3/50=1/25
A does 1/25 work in in 1 day
Therefore 1 work in 25 days.

1 16
Q:

A can write 32 pages in 6 hours and B can write 40 pages in 5 hours. If they write together, in how many hours they can write 110 pages ?

 A) 7 hrs B) 6 hrs 10 min C) 5 hrs 25min D) 8 hrs 15 min

Explanation:

A can write in 1hour = 32/6 pages
similarly
B in 1 hour = 40/5 pages

Together (A+B) in 1 hour = 32/6 + 40/5 = 40/3
so,
A+B write 40/3 pages in 1 hour
A+B write 110 pages in (3/40) x 110 Hours = 8 hours 15 min.

1 25
Q:

There is sufficient salary to give K for 10 days and L for 15 days. Then how many days will the money last if both has to be given the salary ?

 A) 6 days B) 12 days C) 4 days D) 9 days

Explanation:

K's 1 day's salary = 1/10
L's 1 day's salary = 1/15
Together their 1 day's salary = 1/10 + 1/15
= 3/30 + 2/30
= 5/30
= 1/6
So the money will be
enough for paying them both for 6 days.

1 24
Q:

4 men can repair a road in 7 hours. How many men are required to repair the road in 2 hours ?

 A) 17 men B) 14 men C) 13 men D) 16 men

Explanation:

M x T / W = Constant
where, M= Men (no. of men)
T= Time taken
So, here we apply
M1 x T1/ W1 = M2 x T2 / W2
Given that, M1 = 4 men, T1 = 7 hours ; T2 = 2 hours, we have to find M2 =?
Note that here, W1 = W2 = 1 road, ie. equal work load.
Clearly, substituting in the above equation we get, M2 = 14 men.

2 39
Q:

If 6 engines consume 24 metric tonnes of coal, when each is working 8 hours day, how much coal will be required for 9 engines, each running 13hours a day, it being given that 2 engines of former type consume as much as 3 engines of latter type ?

 A) 45 metric tonnes B) 47 metric tonnes C) 55 metric tonnes D) 34 metric tonnes