Answer:
The consumption of pizza falls down by 15.5%.
Explanation:
Given : Stephanos spends all of his $500 allowance on slices of pizza and gas for his pickup truck. He spends eighty percent of this on pizza and the rest on gas. Because of a shortage of gas, the price of gas increases by 40%. This makes his consumption of gas (measured in gallons) fall by 40%.
To find : What is the percentage change in his consumption of pizza ?
Solution :
He spends eighty percent of this on pizza and the rest on gas.
i.e.
He spends $400 on pizza
He spends 500-400=$100 on gas
Let the price of pizza be '
' and price of gas is '
'.
Let Amount of pizza consumed be
and amount of gas be
So,
...(1)
.....(2)
Because of a shortage of gas, the price of gas increases by 40%.
The price of gas is now 140% of what it was earlier.
New price =
Price increase makes his consumption of gas (measured in gallons) fall by 20%.
He is consuming 80% of the gas now as compared to the previous amount
Total amount now spent on gas =
Total amount now spent on gas =
Total amount now spent on gas =
Total amount now spent on gas = Rs.112
If he keeps spending all his money on pizza and gas,
His current expenditure on Pizza = Rs. 500 -112 =Rs.388
Let
Total percentage change in expenditure of pizza is given by,
Therefore the consumption of pizza falls down by 15.5%.