-
If average of two numbers x and 1 (where x ≠ 0) is A, what will be the average of x3 1 ? x x3
-
- 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 |