Standard Mathematics Primary 6 Ratio

A bag contains 56 marbles. The ratio of red marbles to the total number of marbles is 3 : 8. How many marbles are NOT red?

A 35
B 28
C 21
D 24
Show Worked Solution

Worked Solution

Step 1: Identify what 8 units represents. 8 units = total marbles = 56. Step 2: Find 1 unit. 1 unit = 56 ÷ 8 = 7 marbles. Step 3: Find marbles that are NOT red. Not-red = 8 − 3 = 5 units, so not-red = 5 × 7 = 35 marbles. Answer: 35

Correct answer: 35

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