Question

A restaurant sells burgers and fries. If two burgers and one order of fries cost $5.10, and one burger and two orders of fries cost $4.80, how much is one burger and one order of fries?

Answer 1

Answer: Burger $ 1.80, Fries $ 1.50

Step-by-step explanation:

Application of Simultaneous Equations;

let :Burgers = x

let :Fries = y

Equation 1: 2x + y  = 5.10

Equation 2: x + 2y = 4.80

let y be the subject of the formula in Equation 1

Equation 3: y = 5.10 - 2x

Substitute Equation 3 in Equation 2

In the place of y, substitute 5.10 - 2x

x + 2(5.10 - 2x) = 4.80

x + 10.20 - 4x = 4.80

Transpose & Add like terms

-3x = -5.80

Divide by negative 3 both sides

x = 1.80

substitute the value of x in Equation 3

y = 5.10 - 2(1.80)

y = 1.50

Therefore one Burger costs: $ 1.80 and one order of fries : $ 1.50