R=x(A+B)
divide both sides by x
R/x=A+B
minus B both sides
(R/x)-B=A
A=(R/x)-B
X = 30 because the ratio of 27/45 = .6 so 18/.6 is 30
It most common to round to the hundredths place, this is two spaces after the decimal.
So look two spaces right - 0.17. If the third digit (in this case 6) is higher than 5 you round the number up if its not, keep it the same.
"6" is greater than five, so round it to about (or approximately) 0.18.
