How do you reduce the ratio 250: 400

You can divide by 10 and with that its simplified to 25;40...

then you can divede by 5 with that simplified its 5;8

So the answer is 5:8

250:400
Divide by a common factor, let's say 50.
250/50 : 400/50
5 : 8

It's okay if you choose another factor, say 10. It's just more steps.
250/10 : 400/10
25 : 40, now divide by common factor of 5.
5 : 8

The correct answer is d. (0,5)