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Number problem. The sum of the digits in a three-digitnumber is 14. The sum of the hundreds digit and the unitsdigit is equal to the tens digit. If the hundreds digit and theunits digit are interchanged, the number is increased by 297.What is the original number?

User Aelor
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1 Answer

5 votes

Answer: 275

Step-by-step explanation:

Let x represent the hundred digit

Let y represent the tens digit

Let z represent the unit digit

The sum of the digits in a three-digit number is 14. This means that

x + y + z = 14

The sum of the hundreds digit and the units digit is equal to the tens digit. This means that

x + z = y

If the hundreds digit and the units digit are interchanged, the new digit would be x + 10y + 100z. If the number is increased by 297, then

x + 10y + 100z = 100x + 10y + z + 297

x - 100x + 10y - 10y + 100z - z = 297

- 99x + 99z = 297

Substituting y = x + z into the first equation, we have

x + x + z + z = 14

2x + 2z = 14

Dividing through by 2,

x + z = 7

Substituting x = 7 - z into - 99x + 99z = 297, we have

- 99(7 - z) + 99z = 297

- 693 + 99z + 99z = 297

99z + 99z = 297 + 693

198z = 990

Dividing both sides by 198, we have

z = 990/198

z = 5

x = 7 - z = 7 - 5

x = 2

y = x + z = 2 + 5

y = 7

Thus, the original number is

275

User Osaxma
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