Given 10^{0.48} = x, 10^{0.70} = y, and x^z = y^2, find z (approximate).
Aptitude
Surds and Indices
Difficulty: Medium
Choose an option
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A2.50
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B2.75
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C2.92
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D3.10
Answer
Correct Answer: 2.92
Explanation
Given data
- x = 10^{0.48}, y = 10^{0.70}, and x^z = y^2.
Concept / Approach
- Use logarithms/exponent rules: (10^{a})^{b} = 10^{ab}.
Step-by-step calculation
x^z = (10^{0.48})^{z} = 10^{0.48z}y^2 = (10^{0.70})^{2} = 10^{1.40}Equate exponents: 0.48z = 1.40 ⇒ z = 1.40 / 0.48 = 140/48 = 35/12 ≈ 2.92.
Verification
(10^{0.48})^{35/12} = 10^{(0.48×35/12)} = 10^{1.40} = (10^{0.70})^2.
Common pitfalls
- Adding 0.48 and 0.70 or squaring incorrectly; remember to equate exponents.
Final Answer
2.92 (approximately).