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%. if he keeps spending all his money on pizza and gas, what is the percentage change in his consumption of pizza (measured in slices)?

The consumption of pizza falls down by 15.5%.

Step-by-step 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%.