Question

If a:b=8:7 then show that (7a-3b):(11a-9b)=7:5

Answer 1

Step-by-step explanation:

a:b=8:7

=> a/b=8/7

=> a = 8b/7

(7a-3b):(11a-9b)

= (7a-3b)/(11a-9b)

= (7×8b/7 - 3b)/(11×8b/7 - 9b)

= (8b - 3b)/(11×8b/7 - 9b)

= 5b/(25b/7)

= 5×7b/25b

= 7/5

= 7:5 (proved)