Answer:
Cost of one burger, a = $3.35
Cost of one fries, b = $0.9
Cost of one drink, c = $1.1
Step-by-step explanation:
Let
a be cost of one burger
b be the cost of on fry
c be the cost of on drink
So for the 1st group, 4a+5b+7c = $25.60 -----------(1)
for the 2st group, 8a+5b+6c = $37.90 ----------(2)
for the3st group, 12a+10b+11c = $61.30 ----------(3)
Now solving (1) and (2)
That is (1) x 2 - (2) gives,
5b+8c = 13.80 ----------------------(4)
Now, (1) x 3 - (3), we get
5b+10c = 15.5 ---------------------(5)
Solving (4) and (5), we get
c = 1.1
Now putting c in equation (4), we get
b = 0.9
Now from (1), we get
4a+5b+7c = $25.60
4a+5(0.9)+7(1.1) = $25.60
a = 3.35
Cost of one burger, a = $3.35
Cost of one fries, b = $0.9
Cost of one drink, c = $1.1
