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In a bag, the ratio of red marbles to blue marbles is 7:3. If the bag contains 200 marbles, how many red marbles are there?

medium 2 marks Class 6 · Mathematics · Ratio and Proportion
Answer
140

The correct answer is 140 — So there are 140 red marbles.

Step-by-step solution

  1. Total parts in the ratio = 7 + 3 = 10.
  2. Each part equals total marbles ÷ total parts = 200 ÷ 10 = 20.
  3. Red marbles = 7 parts × 20 marbles/part = 140.
  4. So there are 140 red marbles.
Common mistake: dividing total by 7 instead of 10, misreading the ratio.

Concept tested: using parts of a ratio

Published · How this solution was prepared and checked

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