16.
The ratio of the rate of flow of water in pipes varies inversely as the square of the radius of the pipes. What is the ratio of the rates of flow in two pipes of diameters 2 cm and 4 cm?
- A.1 : 2
- C.1 : 8
- B.2 : 1
- D.4 : 1
- Answer & Explanation
- Report
Answer : [D]
Explanation :
Explanation :
| Radii of the two pipes are 1 cm and 2 cm. | ||||||||||
| Squares of the radii of the two pipes are 1cm and 4cm. | ||||||||||
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17.
A precious stone worth Rs. 6,800 is accidentally dropped and breaks into three pieces. The weight of three pieced are in the ratio 5 : 7 : 8. The value of the stone is proportional to the square of its weight. Find the loss.
- A.Rs. 4,260
- C.Rs. 4,454
- B.Rs. 4,273
- D.Rs. 3.250
- Answer & Explanation
- Report
Answer : [C]
Explanation :
Explanation :
| Total weight of the stone = 5 + 7 + 8 = 20 | ||||||
| Given value α (weight)2 | ||||||
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| Therefore, value of the pieces = K (5)2 + K (7)2 + K (8)2 | ||||||
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18.
The monthly incomes of two persons are in the ratio of 4 : 5 and their monthly expenditures are in the ratio of 7 : 9. If each saves Rs. 50 a month. Then what are their monthly incomes?
- A.Rs 100, Rs 125
- C.Rs 300, Rs 375
- B.Rs 200, Rs 250
- D.Rs 400, Rs 500
- Answer & Explanation
- Report
Answer : [D]
Explanation :
Explanation :
| Let the incomes of the two persons be 4I and 5I respectively. | |||||
| Let the expenditure of the two persons be 7E and 9E respectively. | |||||
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19.
The cost of a bat increased by 10% and the cost of a ball increased by 18%. Before the price rise, the ratio of the cost of the bat to the cost of the ball was 9 : 2. If the cost of 12 bats and 54 balls before the price rise was Rs C, what is their cost (in Rs) now?
- A.1.12 C
- C.1.14 C
- B.1.13 C
- D.1.15 C
- Answer & Explanation
- Report
Answer : [C]
Explanation :
Explanation :
| Let the prices of a bat and a ball be 9x and 2x respectively | |||||||||||
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20.
Two numbers are in the ratio 2 : 3. If eight is added to both the numbers, the ratio becomes
3 : 4. The numbers are
3 : 4. The numbers are
- A.15 and 20
- C.13 and 17
- B.16 and 24
- D.17 and 9
- Answer & Explanation
- Report
Answer : [B]
Explanation :
Explanation :
| Let x and y be the numbers | |||||||||||||||||||||
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