SOLUTION: Two numbers are in the ratio of 3:7. Find the numbers if their sum is 90.

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Question 290285: Two numbers are in the ratio of 3:7. Find the numbers if their sum is 90.
Found 2 solutions by richwmiller, jim_thompson5910:
Answer by richwmiller(17219) About Me  (Show Source):
You can put this solution on YOUR website!
3x+7x=90
10x=90
x=9
3*9=27
7*9=63
check
27/63=3/7
ok

Answer by jim_thompson5910(35256) About Me  (Show Source):
You can put this solution on YOUR website!
If "Two numbers are in the ratio of 3:7", then x%2Fy=3%2F7 where 'x' and 'y' are the two unknown numbers. Solve for 'y' to get y=%283%2F7%29x. Because "their sum is 90", we know that x%2By=90. Plug in y=%283%2F7%29x to get x%2B%283%2F7%29x=90. From here, multiply EVERY term by the LCD 7 to clear out the fractions and get 7x%2B3x=630. Simply solve this equation for 'x' and then use this to find 'y'.