The variable y varies directly as x^2 and inversely as z. If y = 15 when x = 3 and z = 6, what is y when x = 4 and z = 5?
Answer and explanation
Correct answer: B. 32
- Step 1: Relationship: y = k x^2 / z. Step 2. Find k: 15 = k 9 / 6 => 15 = 1.5k => k = 10. Step 3. Evaluate: y = 10 (4^2) / 5 = 10 16 / 5 = 2 16 = 32. Answer: 32. Why not the others:* 24 results from neglecting the exponent on x.
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