If a b = 205 then find out the value of (13a-9b) (11a-7b) - mathselab.com

If a : b = 20:5 then find out the value of (13a-9b): (11a-7b)?

Question


If a : b = 20:5 then find out the value of (13a-9b): (11a-7b)?


A. 43/42
B. 40/33
C. 43/37
D. 44/37


Answer: C – 43/37


Solution:


a : b = 20 : 5

a/b = 20/5 = 4

=> a = 4b


=> (13a – 9b) : (11a – 7b)

=> (13 (4b) – 9 (b)) / (11 (4b) – 7 (b))

=> 52b – 9b / 44b – 7b

=> 43b / 37b

=> 43/37


(13a – 9b) : (11a – 7b) Answer is 43/37.




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