A:B = 7:5, B:C = 3:4. Now If C is 30, what is A?

a) 42 (b) 47.5 (c) 40 (d) 31.5

• given b/c = 3:4
  c= 30
  so it becomes as b/30 = 3:4
  cross multiply b=90/4 = 22.5
  
  also given a:b = 7:5
  put b=22.5
  
  a/22.5 = 7/5
  a= 22.5*7/5
  a= 31.5
  
• 10 years agoHelpfull: Yes(5) No(0)
• ans is (d) 31.5
  A=(7/5)B
  B=(3/4)C
  THEN A=(21/20)C
  A=(21*30)/20=31.5
• 10 years agoHelpfull: Yes(1) No(0)
• (A/B)*(B/C)=(7/5)*(3/4)
  A/C=21/20
  A=(21*C)/20
  A=31.5
• 8 years agoHelpfull: Yes(1) No(0)
• Answer 31.5
  
  A:B=7:5, we can write this as A/B=7/5, 5A-7B=0----Eq.1
  from B:C=3:4, and c is given so we can place it here, B:30=3:4 so, B=3*30/4
  
  
  now put this B into Eq.1....we get A=31.5
• 10 years agoHelpfull: Yes(0) No(0)
• b/30=3/4
  b=45/2
  a=7*45/5*2
  a=31.5
• 8 years agoHelpfull: Yes(0) No(0)
• Option (d)
  
  A/B=7/5 ; B/C=3/4
  A/C=21/20 ; C=30
  A=63/2 = 31.5
• 6 years agoHelpfull: Yes(0) No(0)