The method I use for ratio is to find the total amount of ‘splits’ and divide the total by this, and then times the split by the answer, this sounds confusing, but is easy in practice.
1/4
Our total is 5
7800/5=1560
1*1560= 1560
4*1560=6240
Therefore the answer is 1560:6240
Using this method 1/6 would be
1114.3:6685.7
And 1:8 would be
866.7:6993.6
With the last two I have rounded to one d.p
