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# Maths Quiz for KVS/NVS & CTET Exams

Q4. The average weight of 3 men A, B and C is 84 kg. Another man D joins the group and the average now becomes 80 kg. If another man E whose weight is 3 kg more than that of D, replaces A, then the average weight of B, C, D and E becomes 79 kg. The weight of A is:

(a) 76
(b) 65
(c) 75
(d) 50

Q5. There were 35 boys in a hostel. If the number of boys increases by 7, the expenses of the mess increase by Rs. 42 per day while the average expenditure per head diminishes by Re 1. Find the original expenditure of the mess.
(a) 430
(b) 440
(c) 420
(d) 350

Q6. The average monthly salary of the workers in a workshop is Rs. 8500. If the average monthly salary of 7 technicians is Rs. 10000 and average monthly salary of the rest is Rs. 7800, the total number of workers in the workshop is:
(a) 18
(b) 20
(c) 22
(d) 24

Q7. The average age of three boys is 16 years. If their ages are in the ratio 4 : 5 : 7, then the age of the youngest boy is:
(a) 8 years
(b) 9 years
(c) 12 years
(d) 16 years

Q8. What quantity of water should be taken out to concentrate 16 litres of 30% acidic liquid to 40% acidic liquid?
(a) 5l
(b) 6l
(c) 4l
(d) 8l

Q9. Two numbers are less than a third number by 30% and 37% respectively. How much percent is the second number less than the first?
(a) 10%
(b) 15%
(c) 20%
(d) 25%

Q10. Anupam purchased 5 Lemons for Rs. 4. He sold all the Lemons and earned 75% Profit. At what rate did he sell the Lemons?
(a) 4.1 Rs
(b) 1.4 Rs
(c) 2 Rs
(d) 3 Rs

Solutions

S4. Ans.(c)
Sol. A + B + C = (3 × 84) kg = 252 kg
A + B + C + D = (4 × 80) kg = 320 kg
D = (320 – 252) kg = 68 kg
E = (68 + 3) kg = 71 kg
B + C + D + E = (4 × 79) kg = 316 kg
B + C + D = (316 – 71) kg = 245 kg
A = (320 – 245) kg = 75 kg

S5. Ans.(c)
Sol. Suppose the average expenditure was Rs. x. Then total expenditure = 35x.
When 7 more boys join the mess, total expenditure = 35x + 42
Now, the average expenditure
=(35x+42)/(35+7)=(35x+42)/42
Now, we have (35x + 42)/42 = x – 1
Or, 35x + 42 = 42x – 42
Or, 7x = 84
⇒ x = 12
Thus the original expenditure of the mess
= 35 × 12 = Rs. 420

S6. Ans.(c)
Sol. Let the total number of workers be x. Then,
(7 × 10000) + (x – 7) 7800 = 8500x
⇒ 70000 + 7800x – 54600 = 8500x
⇒ 700x = 15400
⇒ x = 22
∴ Total number of workers in the workshop = 22

S7. Ans.(c)
Sol. Sum of the ages of 3 boys = (16 × 3) = 48 years
Ratio of their ages = 4 : 5 : 7
Age of the youngest = 48 × (4/16) = 12 years

S8. Ans.(c)
Sol. Quantity of evaporated water = Original quantity of solution (% Difference of water)/(Final % of water)
= 16 ((40-30)/40)=4l

S9. Ans.(a)
Sol. Let the 3rd number be 100.
Then, 1st number = 70, 2nd number = 63
2nd number is less than 1st by = (7/70) × 100%
= 10%

S10. Ans.(b)
Sol. Cost price for 5 Lemon is Rs. 4
So SP for 5 Lemon = 4 × ((100 + 75)/100) = Rs. 7
So, SP for 1 Lemon = 7/5 = Rs. 1.4