MATH MCQS for JEST/PST

 

MATH MCQs for JEST /PST

 

Two pipes P and Q can fill a cistern in 12 minutes and 16 minutes respectively.  Simultaneously both the pipes are opened together, then after how much time Q should be closed so that the tank is full in 9 min ?

A. 2 min
B. 3 min
C. 4 min
D. 5 min

Let Q be closed after x min.  Then part filled by (P+Q) in x min + part filled by P in ( 9 – x )min
x(1/12+1/16)+(9−x)1/12=1

If X and Y complete a certain work in 10 days, Y and Z in 16 days and X and Z in 22 days, find the time required for each one to complete the work while working separately.

A. 120, 40, 60 days
B. 120, 60, 80 days
C. 40, 30, 120 days
D. 30, 40, 60 days

Let a: be the time in which X & Y completes their work = 30 days
b: time in which Y & Z completes their work = 24 days
c: time in which X & Z completes their work = 40 days
X alone can complete the work in (2 * a * c) / (ab + bc – ac) days
= 2 * 30 * 24 * 40 / ((30 * 24) + (24 * 40) – (30 * 40)) = 120 days
Y alone can complete the work in 2 * a * b * c / (- ab + bc + ac) days
= 2 * 30 * 24 * 40 / (-(30 * 24) + (24 * 40) + (30 * 40)) = 40 days
Z alone can complete the work in 2 * a * b * c / (ab – bc + ac) days
= 2 * 30 * 24 * 40 / ((30 * 24) – (24 * 40) + (30 * 40))
= 60 days

 

 

    HomeMathematics McqsThe speed of a motor boat is that of the current of water as 36:5. The boat goes along with the current in 5 hours 10 min, it will come back in_______?

 

The speed of a motor boat is that of the current of water as 36:5. The boat goes along with the current in 5 hours 10 min, it will come back in_______?

 

A. 5 hours 50 min

B. 6 hours

C. 6 hours 50 min

D. 12 hours 10 min

 

Explanation:

 Let the speed of motor boat be 36x km/hr and that of current of water be 5x km/hr

 Speed downstream = (36x +5x)km/hr = 41x km/hr

Speed upstream = (36 -5x)km/hr = 31x km/hr

Distance covered downstream = (41x × 31/6)km

Distance upstream = [1271x/6 × 1/31x]hrs

= 41/6 hrs = 6hrs 50 min

60% of a number is added to 120, the result is the same number. Find the number?

A. 300
B. 200
C. 400
D. 500

Explanation:

(60/100) * X + 120 = X
2X = 600
X = 300

  Home Mathematics Mcqs After decreasing 24% in the price of an article costs Rs.912. Find the actual cost of an article?After decreasing 24% in the price of an article costs Rs.912. Find the actual cost of an article?

 A. 1400

B. 1300

C. 1200

D. 1100

 Explanation:

CP* (76/100) = 912

CP= 12 * 100 => CP = 1200

What percent of 120 are 90?

A. 25%
B. 50%
C. 75%
D. 33%
Explanation:

(?% /100) * 120 = 90
? = 75%

Today is khadija’s birthday. After one year, she will become two times as she was ten years ago. current age of Khadija?

0

A. 19
B. 20
C. 21
D. 22

let her age be x

after 1 year her age will be x+1=2(x-10)

x+1=2x-20

1+20=2x-x

x=21 years

P and Q can complete a work in 15 days and 10 days respectively. They started the work together and then Q left after 2 days. P alone completed the remaining work. The work was finished in__________days.

A. 12
B. 15
C. 22
D. 20

Work done by P in 1 day = 1/15
Work done by Q in 1 day = 1/10
Work done by P and Q in 1 day = 1/15 + 1/10 = 1/6
Work done by P and Q in 2 days = 2 × (1/6) = 1/3
Remaining work = 1 – 1/3 = 2/3
Time taken by P to complete the remaining work 2/3 = (2/3) / (1/15) = 10 days
Total time taken = 2 + 10 = 12 days

If 6 men can make 10 sofas in 2 days, then 8 men can make 8 sofas in__________?

A. 1.8 days
B. 1.5 days
C. 1.2 days
D. 1 day

Time is
directly proportional to number of sofas
inversely proportional to number of people No. of days
= (6/8)*(8/10)*2
= 1.2 days

Farjan and Kashif can complete a task in 30 days. Farjan leaves after 20 days and Kashif alone completes it in another 25 days. How many days does Farjan alone take to complete the entire task?

A. 50
B. 75
C. 60
D. 45

Part of work completed by Farjan and Kashif in a day
= 1/30 Part of work completed by them in 20 days
= 20/30 = 2/3 1/3 of the work is remaining. Kashif completes 1/3rd of the work in 25 days. Part of work completed by him in a day
= (1/3)÷25
= 1/75 (1/D)+(1/V) = 1/30 (1/D) = (1/30)-(1/75) = 1/50 Farjan can complete it in 50 days.

P is able to do a piece of work in 15 days and Q can do the same work in 20 days. If they can work together for 4 days, what is the fraction of work left?

A. 8/15
B. 7/15
C. 11/15
D. 2/11

Amount of work P can do in 1 day = 1/15
Amount of work Q can do in 1 day = 1/20
Amount of work P and Q can do in 1 day = 1/15 + 1/20 = 7/60
Amount of work P and Q can together do in 4 days = 4 × (7/60) = 7/15
Fraction of work left = 1 – 7/15= 8/15

P,Q and R together earn Rs.1620 in 9 days. P and R can earn Rs.600 in 5 days. Q and R in 7 days can earn Rs.910. How much amount does R can earn per day?

A. Rs.40
B. Rs.70
C. Rs.90
D. Rs.100

Amount Earned by P,Q and R in 1 day = 1620/9 = 180 —(1)
Amount Earned by P and R in 1 day = 600/5 = 120 —(2)
Amount Earned by Q and R in 1 day = 910/7 = 130 —(3)
(2)+(3)-(1) => Amount Earned by P , Q and 2R in 1 day
– Amount Earned by P,Q and R in 1 day = 120+130-180 = 70
=>Amount Earned by R in 1 day = 70

A work can be finished in 16 days by twenty women. The same work can be finished in fifteen days by sixteen men. The ratio between the capacity of a man and a woman is_________?

A. 1:3
B. 4:3
C. 2:3
D. 2:1

Work done by 20 women in 1 day = 1/16

Work done by 1 woman in 1 day = 1/(16×20)
Work done by 16 men in 1 day = 1/15

Work done by 1 man in 1 day = 1/(15×16)
Ratio of the capacity of a man and woman =1/(15×16) : 1/(16×20) = 1/15 : 1/20

= 1/3 :1/4 = 4:3