SOLUTION: One number is 3 more than twice the other number. If the sum of the two numbers is 21, find the two numbers.

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Question 1065121: One number is 3 more than twice the other number. If the sum of the two numbers is 21, find the two numbers.
Answer by JulietG(1812) About Me  (Show Source):
You can put this solution on YOUR website!
Let A be the first number and B be the second.
What do we know from the problem?
A + B = 21
A = 2B + 3
Substitute the value of A from the second equation into the first.
A + B = 21
(2B+3) + B = 21
3B + 3 = 21
3B = 18
Divide
B = 6
If B is 6, then A is "3 more than twice" this. 3+2(6) = 3+12 = 15
To check the answer, put the values back into the original equation.
Does 15 + 6 = 21? Yes
Success!