Question 664368
Set the variables
x = jim
y = tom
...
Given
x = y-3
x+y=7.8
Substitute x into the second equation
y-3+y=7.8
Group like terms
2y - 3 = 7.8
2y = 7.8 + 3
Isolate y, divide both sides by 2
2y = 10.8
y = $5.40 spent by Tom
x = 5.4 - 3 = $2.40 spent by Jim
...
Check
5.40 + 2.40 = 7.80
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