If 100% of a number = that number multiplied by one then 700% of a number would be that number multiplied by 7, so we just have to work backwards to get our answer.
0.25 * 150 = 37.5
37.5 / 7 = 5.35714285714
If you need to round it could look more like this:
5.357
5.36
or 5.4
Hope this helps.