CA Foundation · Quantitative Aptitude · Ratio and Proportion, Indices and Logarithms
If 3^(x+2) = 243, then the value of x is:
The value of x is 3. Since 243 equals 3⁵, the equation 3^(x+2) = 3⁵ requires the exponents to be equal, so x + 2 = 5. Hence x = 3. Picking 5 would ignore the added 2 in the exponent.
- A2
- B3Correct
- C5
- D7
Explanation
243 = 3⁵, so x + 2 = 5 and x = 3. Choosing 5 is the mistake of equating x directly with the exponent of 243, ignoring the +2.
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