# Find the number of pairs of two numbers whose HCF is 5 and their sum is 50. kindly help!?

### 5 Answers

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• 1 year ago

x + y = 50

HCF = 5

5, 45: 15, 35; [35, 15; 45, 5]

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• Ian H
Lv 7
1 year ago

At first we might think of this list

5, 45

10, 40

15, 35

20, 30

25, 25

But 10 rather than 5 is the HCF with

10, 40 and

20, 30

and 25, 25 obviously has an HCF of 25,

so that just leaves 5, 45 and 15, 35

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• Amy
Lv 7
1 year ago

Both numbers are multiples of 5, so let's call them 5x and 5y.

The constraint is that x and y are positive integers and are relatively prime to each other.

5x + 5y = 50

x + y = 10

List all pairs (x,y) that sum to 10 and meet the stated constraint.

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• Dylan
Lv 6
1 year ago

5a+5b=50

a+b=10 with no common factors

1 and 9

3 and 7

So....

5 and 45

15 and 35

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• Pope
Lv 7
1 year ago

It should take only a moment to check all non-negative integer pairs that are divisible by five and whose sum is 50. Let the first of the pair increase from zero to 25.

0, 50 ... HCF = 50; reject

5, 45 ... HCF = 5

10, 40 ... HCF = 10; reject

15, 35 ... HCF = 5

20, 30 ... HCF = 10; reject

25, 25 ... HCF = 25; reject

I count two qualifiers.

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