4 cups every minute means 240 cups every hour:
4 X 60 (minutes per hour)
The lunch last 2 hours so if 240 cups is every hour then 480 cups would be for 2 hours.
Now covert 480 cups to gallons. It takes 16 cups to make 1 gallon. We would divide 480/16 = 30 gallons
The 2 equations are
-2x + y = -17 ---1)
3x + y = 23 ---2)
we need to have the same coefficient for one of the variables.
Already y variable has the coefficient of 1 for both equations so we can use the equations as it is.
2) - 1) subtract 1) from 2)
3x-(-2x) + y -y = 23-(-17)
5x = 40
x = 8
substituting x = 8 in the 2nd equation
3*8 + y = 23
24 + y = 23
y = -1
solution - (8,-1)
By "inspection" you can write the equation as
.. x + y = 10
Then
.. y = -x +10 . . . . . . . . the desired form
Answer:
88 ... .... . ... . . . ... ............... ....
You have been reading your book for about 7 days
7(10) pages each day + 9 left
70+ 9 = 69
