Question

Bob has hats:scarves=4:3. during the day he sells 25 hats. at the end of the day he has hats:scarves=7:9. work out the number of scarves he has.

Answer 1

Let it be that Bob has 4x hats and 3x scarves. By selling 25 hats, the new ratio became 7:9. Mathematically, this may be expressed as,
7 / 9 = (4x - 25) / 3x
The value of x from the equation above is 15. Therefore, at the beginning of the day Bob has 45 scarves.