Question

If (a-b):(a+b)=1:11 find the ratio (5a+4b+15):(5a-4b+3)

Answer 1

(a–b)/(a+b) = 1/11
a+b = 11a–11b
10a=12b
5a=6b

5a+(4b+15) = 6b+(4b+15)
5a+4b+15 = 10b+15
5a+4b+15 = 5×(2b+3)

5a+(3–4b) = 6b+(3–4b)
5a–4b+3 = 2b+3

(5a+4b+15)/(5a–4b+3) = 5×(2b+3)/(2b+3)
(5a+4b+15):(5a–4b+3) = 5:1