If 4a=5b and 7b=9c, then a:b:c=?

  1. 46:36:28
  2.  44:33:28
  3.  45 : 36 : 28
  4.  36:28:45
Desire Adnan Default Asked on 4th August 2015 in Maths.
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1 Answer(s)

Answer: (3) 45 : 36 : 28
Explanation:-
4 a = 5 b and 7 b = 9 c
Then, a = 5 b/4    and  b = 9 c/7
a/b = 5/4   and  b/c = 9/7
a : b = 5 : 4  and  b : c = 9 : 7
Formula:-
A : B = a : b   & B : C + b : c
Then, A : B : C = a x b : b x b : b x c

Then, a : b = 5 : 4  and  b : c = 9 : 7
a : b : c = 5 x 9 : 4 x 9 : 4 x 7
= 45 : 36 : 28
Then, the value of a : b : c  = 45 : 36 : 28
Hence, the answer is (3) 45 : 36 : 28.

Anurag Mishra Professor Answered on 4th August 2015.
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