Respuesta :
Answer:
Equation 1: 8x + 10y = 123.4
Equation 2: 5x + 9y = 97.2
cost of a burrito = $7.30
cost of a sandwich = $6.30
Step-by-step explanation:
Let x = cost of a sandwich
Let y = cost of a burrito
Equation 1: 8x + 10y = 123.4
Equation 2: 5x + 9y = 97.2
Rewrite equation 1 to make y the subject, then substitute into equation 2 and solve for x:
8x + 10y = 123.4
⇒ 10y = 123.4 - 8x
⇒ y = 12.34 - 0.8x
5x + 9(12.34 - 0.8x) = 97.2
⇒ 5x + 111.06 - 7.2x = 97.2
⇒ 13.86 = 2.2x
⇒ x = 6.3
So cost of a sandwich = $6.30
Substituting x = 6.3 into equation 2 and solving for y:
5(6.3) + 9y = 97.2
⇒ 31.5 + 9y = 97.2
⇒ 9y = 65.7
⇒ y = 7.3
So cost of a burrito = $7.30
Answer:
8x + 10y = 123.40
5x + 9y = 97.20
OR
40x + 50y = 617
-40x - 72y = -777.6
x = $6.30
y = $7.30
Step-by-step explanation:
we can write this system of equations:
8x + 10y = 123.40
5x + 9y = 97.20
using the 'elimination method', we can multiply the first equation by 5 and the second equation by -8 to get:
5(8x + 10y) = 123.4(5)
40x + 50y = 617
-8(5x + 9y) = 97.2(-8)
-40x - 72y = -777.6
now we can add the new equations and solve for 'y':
40x + 50y = 617
-40x - 72y = -777.6
-22y = -160.6
y = 7.30
now we can substitute 7.3 for 'y' so we can solve for 'x':
8x + 10(7.3) = 123.4
8x + 73 = 123.4
8x = 50.4
x = 6.30