They will tip $8.10.
How to Do it/ Work:
18 * 0.45 = 8.1
16 it's just double the the denominator and the top number
Just solve until the answers are the same
25 times x plus 30 for John
15 times x plus 50 for Mary
Step-by-step explanation:
Given.


Take the second equation and subtract 2y to both sides.


Substitute x into the first equation and simplify.




Invert.

Substitute Y into your second equation.



Add -6 to both sides.


Answer:
(6, -3)