Posted by **Lexi** on Tuesday, September 30, 2008 at 12:35am.

When a certain number N is divided by d, the remainder is 7. If the original number N is multiplied by 5 and then divided by d, the remainder is 10.

Find d.

- Maths -
**David Q**, Tuesday, September 30, 2008 at 2:00pm
The answer is d=25; N is any of 7, 32, 57, 82, 107, 132 etc etc. It was set up in a spreadsheet and arrived at by trial and error, so just knowing the answer probably won't get many marks. I'd be interested to know if anyone else can produce a formula for deriving the solution algebraically - because I can't see how to do it either.

## Answer This Question

## Related Questions

- Math - How many integers between 200 and 500 inclusive leave a remainder 1 when ...
- Math - How many integers bewteen 200 and 500 inclusive leave a remainder 1 when ...
- math - What is the lowest numberthat has a remainder of 1 when divided by 2 and ...
- number theory - Find the least positive integer that leaves the remainder 3 ...
- math - what is the least common positive integer that meets the following ...
- math - A certain number has a remainder of 3 when divided by 5. That same number...
- math - what is the least common positive integer that meets the following ...
- Math - Find the least positive integer that leaves the remainder 3 when divided...
- Math - This problem from China is almost 2000 years old: Find a number that when...
- math - This problem from China is almost 2000 years old: Find a number that when...

More Related Questions