Chain Rule - Quantitative Aptitude (MCQ) questions

1)   If a quarter kg of onions costs 80 paise, how many paise will 100 gm cost?
- Published on 13 Apr 16

a. 32 paise
b. 44 paise
c. 56 paise
d. 63 paise
Answer  Explanation 

ANSWER: 32 paise

Explanation:
Let the required cost be x paise.
Less weight, Less cost (Direct proportion)
250 : 100 : : 80 : x
250 * x = (100 * 80)
x = (100 * 80) / 250
x = 32


2)   34 men can complete a piece of work in 18 days. In how many days will 17 men complete the same work?
- Published on 06 Apr 16

a. 12
b. 18
c. 24
d. 36
e. None of these
Answer  Explanation 

ANSWER: 36

Explanation:
Let the required number of days be A.
Then, Less men, More days (Indirect Proportion)
17 : 34 : : 18 : A
17 x A = 34 x 18
A = (34 x 18) / 17
A = 36


3)   If 36 men can do a piece of work in 25 hours, in how many hours will 10 men do it?
- Published on 31 Mar 16

a. 100 hours
b. 90 hours
c. 60 hours
d. 30 hours
Answer  Explanation 

ANSWER: 90 hours

Explanation:
Let the required numbers of hours be X.
Less men, More hours (Indirect proportion)
Therefore, 10 : 36 :: 25 : X = (10 x X) = (36 x 25) = X = (36 x 25)/10 = 90.
Hence, 10 men can do it in 90 hours.


4)   If 15 toys cost Rs. 545, what do 37 toys cost ?
- Published on 25 Mar 16

a. Rs. 1344
b. Rs. 1200
c. Rs. 1668
d. Rs. 1542
Answer  Explanation 

ANSWER: Rs. 1344

Explanation:
Let the required cost be Rs. x.
More toys, More cost (Direct proportion)
Therefore 15 : 37 :: 545 : x
(15 * x) = (37 * 545)
x = (37*545)/15
= 1344.33
Hence, the cost of 37 toys is Rs. 1344.33


5)   For a road work, a contractor was given a deadline to complete the work in 25 days. Hence, he employed a certain number of workers to accomplish the job. But from the very first day 9 workers were absent and the remaining workers could finish the work in 40 days. What number of workers did the contractor hired in the beginning?

- Published on 06 Jul 15

a. 20
b. 30
c. 24
d. 16
Answer  Explanation 

ANSWER: 24

Explanation:
Let the number of workers initially hired be x.

Hence, x workers can complete the work in 25 days and (x-9) workers can complete the work in 40 days.

Now, the number of men and the amount of work are in direct proportion and number of men and number of days in indirect proportion.

x*25 = (x – 9)*40
25x = 40x – 360
15x = 360
x = 24


6)   If a certain number of people can dig earth 100m deep, 25m long, and 30m broad in 12 days, then find the number of days the same number of people will require to dig earth 75m deep, 20m long and 50m broad.
- Published on 06 Jul 15

a. 12
b. 18
c. 6
d. 1
Answer  Explanation 

ANSWER: 12

Explanation:
More number of days means – more length, more depth and more width. Hence, it’s a direct proportion.
(100*25*30):(75*20*50)::12:x
75000:75000::12:x
x = 12


7)   If a carpenter completes 3/8th of his work in 6 days, then how many more days will he require completing his remaining work?
- Published on 06 Jul 15

a. 10
b. 12
c. 6
d. 16
Answer  Explanation 

ANSWER: 10

Explanation:
As 3/8th of the work is completed, the work remaining is 5/8th of the total.
(3/8):6::(5/8):x
x = 6*(5/8)/(3/8)
x = 10


8)   A military camp has a food reserve for 250 personnel for 40 days. If after 15 days 50 more personnel are added to the camp, find the number of days the reserve will last for?
- Published on 06 Jul 15

a. 20
b. 36
c. 25
d. 42
Answer  Explanation 

ANSWER: 25

Explanation:
As the camp has a reserve for 250 personnel that can last for 40 days, after 10 days the reserve left for 250 personnel is for 30 days. Now 50 more personnel are added

in the camp.

Hence, the food reserve for 300 personnel will last for:

250:300::x:30 ……..(it is an indirect proportion as less men means more days)
x = (250*30)/300
x = 25 days


9)   A group of 55 adults and 70 children go for trekking. If there is meal for either 70 adults or 90 children and if 28 adults have their meal, find the total number of children that can be catered with the remaining food.
- Published on 06 Jul 15

a. 42
b. 54
c. 90
d. 70
Answer  Explanation 

ANSWER: 54

Explanation:
As there is meal for 70 adults and 28 have their meal, the meal left can be catered to 42 adults.
Now, 70 adults = 90 children
7 adults = 9 children
Therefore, 42 adults = 54 children
Hence, the meal can be catered to 54 children.


10)    If a cloth merchant sells ‘a’ metres of cloth for Rs.x, then what is the selling price of ‘b’ metres of cloth?

- Published on 06 Jul 15

a. Rs.(b*x)
b. Rs.{(b*x)/a}
c. Rs.{(a*b)/x}
d. None of these
Answer  Explanation 

ANSWER: Rs.{(b*x)/a}

Explanation:
Cost of ‘a’ metres of cloth = Rs.x. Therefore, each metre of cloth costs Rs. (x/a).
The cost of ‘b’ metres of cloth = Rs. b*(x/a) = Rs. {(b*x)/a}


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