SOLUTION: one boy earned 40 dollars more than another boy. Together they have 140 dollars. how much does each boy have

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Question 518125: one boy earned 40 dollars more than another boy. Together they have 140 dollars. how much does each boy have

Answer by RicaMath(8) About Me  (Show Source):
You can put this solution on YOUR website!
Let X = Boy 1
Let Y = Boy 2


We know two things:
1. Boy 1 earned $40 more than Boy 2
2. Together they have $140


Let's put these two statements into equations.


1. Boy 1 earned $40 more than Boy 2
So, this means you take the amount of money that Boy 2 has, add $40, and you will have the amount that Boy 1 has.
X = Y + 40


2. Together they have $140
So, this means adding the two amounts together equals $140
X + Y = 140


Using substitution, we now solve for each variable.

X + Y = 140 (2nd equation)
(Y + 40) + Y = 140 (substitute X for the 1st equation)
2Y + 40 = 140 (simplify)
2Y = 100 (subtract 40 from both sides)
Y = 50


Now that we know Y, let's solve for X:
X = Y + 40
X = 50 + 40 (substitute Y for the value we just found)
X = 90


So, Boy 1 has $90 and Boy 2 has $50.