SOLUTION: THe sum of two numbers is 45. Three times the first number plus seven times the second is 115. Find the two numbers.

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Question 306221: THe sum of two numbers is 45. Three times the first number plus seven times the second is 115. Find the two numbers.
Answer by Fombitz(32388) About Me  (Show Source):
You can put this solution on YOUR website!
Let A and B bet the numbers.
1.A%2BB=45
2.3A%2B7B=115
From eq. 1,
A%2BB=45
A=45-B
Substitute into eq. 2,
3A%2B7B=115
3%2845-B%29%2B7B=115
135-3B%2B7B=115%7D%7D%0D%0A%7B%7B%7B4B=-20
highlight%28+B=-5%29
Then from eq. 1,
A=45-B
A=45-%28-5%29
highlight%28+A=50%29