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# Maths Questions for DSSSB & KVS/NVS Exams

Q1. The average age of 40 girls in a class is 15. The average age of a group of 18 girls in the class is 16 and the average age of another 12 girls in the class is 14. What is the average age of the remaining girls in the class?
(a) 15.25 years
(b) 14.40 years
(c) 14.75 years
(d) 15.25 years

Q2. A dealer bought an item at 10% discount on its original price. He sold it at 35% more than the original price. What percentage of profit did he get?
(a) 25%
(b) 45%
(c) 20%
(d) 50%

Q3. If Rajesh’s salary is 30% more than Amit’s salary, then how many percent of Amit’s salary is less than that of Rajesh’s salary?
(a) ≈ 26%
(b) ≈ 23%
(c) ≈ 20%
(d) ≈ 27%

Q4. The population of a city is 1500000. It increases by 10% during 1st year, decreases by 20% in 2nd year and increases by 30% in the 3rd year. The population after 3 years is?
(a) 1716000
(b) 1750000
(c) 1650000
(d) 1600000

Q5. X, Y and Z undertake to complete a piece of work for Rs 1950. X works for 8 days, Y for 9 days and Z for 12 days to complete the work. If their daily wages are in the ratio of 3 : 5 : 4, what does Z get?
(a) 400
(b) 750
(c) 650
(d) 800

Q6. A radio is sold for Rs. 990 at a profit of 10%. What would have been the gain or loss percentage had it been sold for Rs. 880?
(a) 19/3% gain
(b) 17/3% loss
(c) 17% gain
(d) 20/9% loss

Q7. A person’s present age is two-fifth of the age of his mother. After 8 years, he will be one-half of the age of his mother. How old is the mother at present?
(a) 36
(b) 38
(c) 40
(d) 42

Q8. The least five-digit perfect square number which is divisible by 3, 4, 5, 6, 8 is
(a) 14400
(b) 10800
(c) 10200
(d) 32400

Q9. From a vessel containing 100L of wine, 10L are drawn out and an equal amount of water is added. From the mixture, 10L is again drawn out and same quantity of water is added. What is the final ratio of wine to water?
(a) 90:10
(b) 91:9
(c) 81:19
(d) 80:20

Solutions

S1. Ans.(b)
Sol. Total age of 40 girls are = 40 × 15 = 600
So, Sum of other group of girls are = 18 × 16 + (12 × 14) = 456
Total age of other 10 girls and their average is
= 600-456 = (144/10)
= 14.4 years

S2. Ans.(d)
Sol. Let the original price to be Rs 100
So, he bought it at 10% discount i.e Rs 90 and
sells it at 35% more than the original rate = Rs 135
Actual profit is 135-90 = Rs 45
So profit% = (45/90) × 100 = 50%

S3. Ans.(b)
Sol. Amit’s salary is less than of Rajesh by:
= (30/(100 + 30)) × 100) %
= 300/13%
= 23% approx

S4. Ans.(a)
Sol. Initial population = 1500000
After first year increment of 10% population
= 1500000 + (10/100 × 1500000) =1650000
After 2nd year decrement of 20% population
= 1650000 – (20/100 × 1650000) = 1320000
After increment of 30% in 3rd year
= 1320000 + (30/100 × 1320000) = 1716000

S5. Ans.(d)
Sol. Daily wages are in the ratio 3:5:4
Working days of X,Y & Z = 8, 9 and 12
So, the wages they will get in the ratio are =  24:45:48
Share of Z = (48/ (24+45+48)) × 1950 = Rs 800

S6. Ans.(d)
Sol. Let the CP is Rs. x
Then, (x × 110)/100 = 990
x = Rs. 900
Now CP is Rs 900 and SP is Rs 880
% loss = (20/900) × 100 = 20/9%

S7. Ans.(c)
Sol. Let the mother’s present age be x years
Then, the person’s present age = (2 x /5) years
Therefore, (2 x /5) + 8 = ½(x+8)
x= 40 years.

S8. Ans.(a)
Sol. LCM of 3,4,5,6 and 8 = 120. Now, by seeing the option,
we get that 14400 is least five-digit perfect square number which is divisible by 120.

S9. Ans.(c)
Sol. Here, a= 10L, n=2 and x=100L
Quantity of wine in the end= x(1-a/x)^n
=100(1-10/100)^2 = 81L
Required ratio= 81:(100-81) =81:19