ACT Math · Ratios, rates, and percents
The variable y varies inversely with x. If y = 8 when x = 3, what is y when x = 6?
The variable varies inversely with . If when , what is when ?
Answer and explanation
Answer: G: 4
Inverse variation means , so the product stays constant. From the given values, . When , , choice G. Doubling from to cuts in half, from to . Choice F () treats the relationship as direct variation, doubling when doubles. Choice H () divides by , dividing twice instead of once. Choice J () reports the constant itself instead of the value of . A quick check: , so the product is unchanged.
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