Andrea and her friends bought 11 fries and 8 hamburgers
Solution:
Let "f" be the number of fries bought
Let "h" be the number of hamburgers bought
Cost of 1 fries = $ 2.50
Cost of 1 hamburger = $ 4.75
Given that Andrea and her friends ordered 19 items
number of fries bought + number of hamburgers bought = 19
f + h = 19 ---- eqn 1
They ordered for total of 65.50
number of fries bought x Cost of 1 fries + number of hamburgers bought x Cost of 1 hamburger = 65.50
[tex]f \times 2.50 + h \times 4.75 = 65.50[/tex]
2.5f + 4.75h = 65.5 --- eqn 2
Let us solve eqn 1 and eqn 2
From eqn 1,
f = 19 - h ----- eqn 3
Substitute eqn 3 in eqn 2
2.5(19 - h) + 4.75h = 65.5
47.5 - 2.5h + 4.75h = 65.5
h = 65.5 - 47.5
2.25h = 18
Substitute h = 8 in eqn 3
f = 19 - 8 = 11
Thus they bought 11 fries and 8 hamburgers
