SOLUTION: Martha and Sally had lunch together on Tuesday. Sally paid $2 more than Martha. If the total bill was $5.64. How much did Sally pay for her lunch? I need the answer :)

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Question 147896: Martha and Sally had lunch together on Tuesday. Sally paid $2 more than Martha. If the total bill was $5.64. How much did Sally pay for her lunch?
I need the answer :)

Answer by Fombitz(32388) About Me  (Show Source):
You can put this solution on YOUR website!
Let's call the cost of Martha's lunch, M.
Sally's lunch cost will be S.
You know the total was $5.64.
1.M%2BS=5.64
You also know that Sally paid $2.00 more than Martha.
2.S=2.00%2BM
If you substitute the value for S in eq. 2 into eq. 1, you can solve for M.
1.M%2BS=5.64
M%2B%282.00%2BM%29=5.64
2.00%2B2M=5.64
2M=3.64
M=1.82
Now you know Martha's lunch was $1.82, use eq. 2 to solve for Sally's cost,
2.S=2.00%2BM
S=2.00%2B1.82
S=3.82
Sally paid $3.82.