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Two bags each contain only red counters and yellow counters - OCR - GCSE Maths - Question 6 - 2017 - Paper 1

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Two bags each contain only red counters and yellow counters. In Bag A, the ratio of red counters to yellow counters is 1 : 4. In Bag B, \( \frac{1}{4} \) of the c... show full transcript

Worked Solution & Example Answer:Two bags each contain only red counters and yellow counters - OCR - GCSE Maths - Question 6 - 2017 - Paper 1

Step 1

(i) Explain why Sharon is not correct.

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Answer

Sharon is not correct because the proportions of red counters to total counters differ between the two bags. In Bag A, the ratio of red to yellow counters is 1:4, meaning there are 1 red counter for every 4 yellow counters. This gives a proportion of red counters as follows:

Proportion of red in Bag A=11+4=15=0.2 or 20%.\text{Proportion of red in Bag A} = \frac{1}{1+4} = \frac{1}{5} = 0.2 \text{ or } 20\%.

In Bag B, where ( \frac{1}{4} ) of the counters are red, the proportion of red counters is:

Proportion of red in Bag B=14=0.25 or 25%.\text{Proportion of red in Bag B} = \frac{1}{4} = 0.25 \text{ or } 25\%.

Thus, the proportions of red counters are not the same: 20% in Bag A and 25% in Bag B.

Step 2

(ii) Complete the table below to show how many counters of each colour could be in the bags.

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Answer

Assuming the total number of counters in both bags is the same, the quantities can be calculated. Let the total number of counters in each bag be ( n ).

In Bag A:

  • Red Counters = ( x = 1 \cdot k )
  • Yellow Counters = ( y = 4 \cdot k )

Total in Bag A: ( n = x + y = k + 4k = 5k )

In Bag B:

  • Since ( \frac{1}{4} ) are red, we have ( \text{Red} = \frac{n}{4} )
  • The remaining counters will be yellow, thus ( \text{Yellow} = n - \frac{n}{4} = \frac{3n}{4} )

This implies:

  • For Bag A, if we let k = 1, then:
    • Red = 1, Yellow = 4, Total = 5
  • For Bag B to keep the same total:
    • Red = 1, Yellow = 3 (as an example keeping total as a multiple of 4)

Hence, the filled table could look like:

| Bag A | 1 | 4 | | Bag B | 1 | 3 |

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