SOLUTION: if ratio of two numbers "a" and "b" is 3 to 4 and their sum is 420. Find a-b

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Question 479145: if ratio of two numbers "a" and "b" is 3 to 4 and their sum is 420. Find a-b
Answer by Tatiana_Stebko(1539) About Me  (Show Source):
You can put this solution on YOUR website!
system%28a%2Fb=3%2F4%2C+a%2Bb=420%29
from the first equation a=%283%2F4%29b substitute into the second equation
%283%2F4%29b%2Bb=420
%287%2F4%29b=420divide by 7
%281%2F4%29b=60multiply by 4
b=240
substitute b=240 into a=%283%2F4%29b, a=%283%2F4%29%2A240=180
Then a-b=180-240=-60