<u>Story Problem</u>
Mr. Bill Gates bought a house in Italy for
and a house in Canada for
. What is the total cost of the two houses?
we know that
The total cost is the sum of the cost each house
so

therefore
the answer is
The total cost is 
X is equal to 8
Y is equal to 0
See attached graph: v is on the y-axis and t is on the x-axis
The fractions you're given can be simplified down, so you get (12 ÷ 3) 4 hours on Monday, (21 ÷ 3) 7 hours on Tuesday, and (22 ÷ 3) 7 1/3 hours on Wednesday. You can now add these up and get your answer as 18 1/3 hours, or 18.33.
I hope this helps!