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If the radius of a right circular cylinder is decreased by 50% and its height is increased by 60%, its volume will be decreased by
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- 10%
- 60%
- 40%
- 20%
- 10%
Correct Option: B
Let the radius of a right circular cylinder is changed by x% and height is changed y%, then Volume change by
 | 2x + y + | + |  | % | |||
| 100 | 100² |
| ∴ Effective change = | | - 2 × 50 + 60 + | + | | % | ||
| 100 | 10000 |
= (–100 + 60 – 35 + 15)
= (75 – 135) = – 60%
Negative sign shows decrease.
