SOLUTION: If a, b, and c are positive numbers such that 3a = 4b = 5c, and if a + b = kc, what is the value of k ? (A) 12/35 (B) 5/7 (C) 10/7 (D) 7/5 (E) 35/12

Algebra ->  Customizable Word Problem Solvers  -> Misc -> SOLUTION: If a, b, and c are positive numbers such that 3a = 4b = 5c, and if a + b = kc, what is the value of k ? (A) 12/35 (B) 5/7 (C) 10/7 (D) 7/5 (E) 35/12      Log On

Ad: Over 600 Algebra Word Problems at edhelper.com


    

Question 253013: If a, b, and c are positive numbers such that 3a = 4b = 5c, and if a + b = kc, what is the value of k ?
(A) 12/35 (B) 5/7 (C) 10/7 (D) 7/5 (E) 35/12
Answer by JimboP1977(311) About Me  (Show Source):
You can put this solution on YOUR website!
%28a%2Bb%29%2Fc=k
Express left handside in terms of a.
%28a%2B%283%2F4%29a%29%2F%28%283%2F5%29a%29=k
%28%287%2F4%29a%29%2F%28%283%2F5%29a%29=k
%28%287a%2F4%29%2A%285%2F3a%29%29=k
35a%2F12a=k
The a terms cancel to give
35%2F12=k