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If average of two numbers x and 1 (where x ≠ 0) is A, what will be the average of x3 1 ? x x3
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- 4A3 - 2A
- 4A3 - 3A
- 4A3 - 4A
- 4A3 - A
- 4A3 - 2A
Correct Option: B
According to the question ,
| A = | 1 + | |
| x | ||
| 2 | ||
| ⇒ x + | = 2A | |
| x |
On cubing both sides,
| ⇒ | ![]() | x + | ![]() | 3 | = (2A)3 = 8A3 | |
| x |
| ⇒ x3 + | + 3 | ![]() | x + | ![]() | = 8A3 | ||
| x3 | x |
| ⇒ x3 + | + 3 × 2A = 8A3 | |
| x3 |
| ⇒ x3 + | = 8A3 - 4A | |
| x3 |
| ∴ Required average = | x3 + | |
| x3 | ||
| 2 | ||
| Required average = | = 4A3 - 2A | |
| 2 |

