Answer:
74
Step-by-step explanation:
Using linear equations, we are given two equations from the questions:
4x +7y=30 from day one and 3x +5y=22 from day two
Multiply the first equation by 3 and second by 4 giving us
12x +21y=90 and 12x +20y=88. Minus both equations.
12x - 12x +21y - 20y= 90 - 88, Gives you y=2,
You can now use the value of y to find x.
4x + 7y = 30
4x + 7(2)= 30
4x + 14= 30. Minus 14 on both sides giving you
4x=16. Divide both sides by 4.
x=4
Now use both values to find how much money is needed on the third day.
10x + 17y
=10(4) + 17(2)
=40 +34
=74
