p and q are two numbers such that p > q - Edexcel - GCSE Maths - Question 18 - 2018 - Paper 2
Question 18
p and q are two numbers such that p > q.
When you subtract 5 from p and subtract 5 from q the answers are in the ratio 5:1.
When you add 20 to p and add 20 to q the... show full transcript
Worked Solution & Example Answer:p and q are two numbers such that p > q - Edexcel - GCSE Maths - Question 18 - 2018 - Paper 2
Step 1
When you subtract 5 from p and subtract 5 from q the answers are in the ratio 5:1.
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Answer
From the first statement, we can write the equation:
q−5p−5=5
Cross-multiplying gives:
p−5=5(q−5)
This simplifies to:
p−5=5q−25
Rearranging gives:
p−5q=−20(1)
Step 2
When you add 20 to p and add 20 to q the answers are in the ratio 5:2.
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Answer
From the second statement, we can write the equation:
q+20p+20=25
Cross-multiplying gives:
2(p+20)=5(q+20)
This simplifies to:
2p+40=5q+100
Rearranging gives:
2p−5q=60(2)
Step 3
Find p and q.
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Answer
Now we have two simultaneous equations:
p−5q=−20
2p−5q=60
Subtracting equation (1) from equation (2):
(2p−5q)−(p−5q)=60+20
This simplifies to:
p=80
Substituting p=80 back into equation (1):
80−5q=−20
This gives:
5q=100⇒q=20
Step 4
Find the ratio p : q.
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