GMAT Quant — Applied Mathematics (Word Problems)

Question

Two ropes, Rope P and Rope Q, each have the same initial length, but Rope P burns completely in minutes while Rope Q burns completely in minutes. They are lit simultaneously at one end. In terms of , after how many minutes will the remaining length of Rope Q be twice the remaining length of Rope P?
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Answer Choices

  • A.
  • B.
  • C.
  • D.
  • E.

Steps

ExplanationCalculationsHelp
We let be the initial length of each rope and let be the elapsed time in minutes.
We express the remaining length of each rope based on its constant burn rate.
Theory & Tactics Method Card
RATE1-C
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We set up the equation for "remaining length of Rope Q be twice the remaining length of Rope P".
We solve the equation by dividing out , clearing denominators, grouping like terms, and isolating .
$\text{Rearrange terms:$
Theory & Tactics Method Card
EQUA1-C
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Final Answer

C