9
Q:

# 50 men can build a tank in 40days, but though they begin the work together, 5 men quit every ten days. The time needed to build the tank is ?

 A) 50 days B) 48 days C) 47.5 days D) 49 days

Explanation:

50 men can build a tank in 40 days
Assume 1 man does 1 unit of work in 1 day
Then the total work is 50×40 = 2000 units

50 men work in the first 10 days and completes 50×10 = 500 units of work
45 men work in the next 10 days and completes 45×10 = 450 units of work
40 men work in the next 10 days and completes 40×10 = 400 units of work
35 men work in the next 10 days and completes 35×10 = 350 units of work
So far 500 + 450 + 400 + 350 = 1700 units of work is completed and

remaining work is 2000 - 1700 = 300 units

30 men work in the next 10 days. In each day, they does 30 units of work.

Therefore, additional days required = $\inline \fn_jvn \small \frac{300}{30}=10$

Thus, total 10+10+10+10+10 = 50 days required.

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 8
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 9
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 24
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

Explanation:

2 engines of former type for one hour consumes 2x24/(6x8) = 1 metric ton
i.e. 3 engines of latter type consumes 1 ton for one hour
hence 9 engines consumes 3 tons for one hour
for 15 hours it is 15 x 3 = 45 metric tonnes.

1 39
Q:

A does half as much work as Band C does half as much work as A and B together. If C alone can finish the work in 40 days, then together ,all will finish the work in  ?

 A) 17 + 4/7 days B) 13 + 1/3 days C) 15 + 3/2 days D) 16 days

Explanation:

C alone can finish the work in 40 days.
As given C does half as much work as A and B together
=> (A + B) can do it in 20 days
(A + B)s 1 days wok = 1/20.
A's 1 days work : B's 1 days Work = 1/2 : 1 = 1:2(given)
A's 1 day’s work = (1/20) x (1/3) = (1/60) [Divide 1/20 in the raio 1:2]
B's 1 days work = (1/20) x (2/3) = 1/30
(A+B+C)'s 1 day's work = (1/60) + (1/30) + (1/40) = 9/120 = 3/40

All the three together will finish it in 40/3 = 13 and 1/3 days.