SOLUTION: The Harnapps and the Curies are going to the Pizza Palace for dinner. The Harnapps order 3 slices of pizza and 3 colas and have a bill that totals $15. The Curies order 4 slices of

Algebra.Com
Question 1205478: The Harnapps and the Curies are going to the Pizza Palace for dinner. The Harnapps order 3 slices of pizza and 3 colas and have a bill that totals $15. The Curies order 4 slices of pizza and 3 colas and have a bill that totals $18. Determine the best method to solve the system of equations. Then
solve the system.

Found 3 solutions by Theo, math_tutor2020, josgarithmetic:
Answer by Theo(13342)   (Show Source): You can put this solution on YOUR website!
harnapps ordered 3 pizza and 3 colas for 15 dollars.
curies ordered 4 pizza and 3 colas for 18 dollars.

since they both ordered 3 colas, then the only difference was curies ordered one extra pizza, so the cost of a pizza had to be 3 dollars because that was the difference in what they paid (18 dollars minus 15 dollars = 3 dollars).

if the pizza was 3 dollars, then harnapps total bill was 15 minus 9 dollars for pizza = 6 dollars for cola.
since they had 3 colas, then the cost of a cola had to be 2 dollars.

to solve this algebraically, you would do the following.

let x = cost of one pizza and y = cost of one cola.

your two equations are:

3x + 3y = 15
4x + 3y = 18
subtract the first equation from the second to get x = 3.
that means cost of a pizza was 3 dollars.
replace x with 3 in either equation and solve for y.
4x + 3y = 18 becomes 4*3 + 3y = 18 which becomes 12 + 3y = 18.
subtract 12 from both sides of the equation to get 3y = 6
solve for y to get y = 2.

solution is cost of a pizza is 3 and cost of a cola is 2.

3x + 3y = 15 becomes 3*3 + 3*2 = 15 which becomes 9 + 6 = 15 which becomes 15 = 15 which is true.
4x + 3y = 18 becomes 4*3 + 3*2 = 18 which becomes 12 + 6 = 18 which becomes 18 = 18 which is also true.
this confirms the solution is good.






Answer by math_tutor2020(3817)   (Show Source): You can put this solution on YOUR website!

If you want to use elimination, then follow tutor Theo's approach when using algebra.
Substitution is another possibility.

--------------------------------------

Here's a way to do it with mental math.
Both families ordered 3 colas. The only difference is that the Curies ordered 1 extra slice of pizza. So each slice of pizza must be 18-15 = 3 dollars, since we just look at the difference of their bills.

Harnapps:
3 slices = 3*3 = 9 dollars
15-9 = 6 dollars spent on colas, so each cola is 6/3 = 2 dollars

Curies:
4 slices = 4*3 = 12 dollars
18 - 12 = 6 dollars spent on colas, so each cola is 6/3 = 2 dollars

--------------------------------------

Answer:
Each pizza slice costs $3
Each cola costs $2

Answer by josgarithmetic(39625)   (Show Source): You can put this solution on YOUR website!
------------------------------------------------------------------
The Harnapps order 3 slices of pizza and 3 colas and have a bill that totals $15. The Curies order 4 slices of pizza and 3 colas and have a bill that totals $18.
-------------------------------------------------------------------

p price of pizza slice
c price of cola drink


To account for each purchase sale,



You should be able to see the difference already between the two equations. Left members are almost the same; just one more p in the second equation. p is 3 dollars.

If you really need or want,

RELATED QUESTIONS

jack bought 3 slices of cheese pizza and 4 slice of mushroom pizza for a total cost of... (answered by vleith)
Jack bought 3 slices of cheese pizza and 4 slices of mushroom pizza for a total cost of... (answered by FrankM,stanbon)
Samantha and Rachel had lunch at the mall. Samantha ordered three slices of pizza and two (answered by fractalier)
Savannah and her father went to Paulo's Pizzeria for pizza with everything except... (answered by CharlesG2)
A large pizza at Pizzas4Less has 12 slices. Jeremiah ate 1 over 6 of the pizza and his... (answered by Boreal)
Which is more pizza the 1/2 of a pizza with 8 slices or 1/3 of a pizza with 12 slices?... (answered by robertb)
Jamie and her friends brought 1 cheese pizza, 1 mashroom pizza and 1 pepperoni pizza.... (answered by tutorcecilia)
Tom, Bill, and Brian order two large pizzas. Tom eats two slices, while Bill and Brian... (answered by checkley77)
Caitlyn and Daniela are going out for pizza to their local gourmet pizza shop. They order (answered by ikleyn)