Question 951431
At the local grocery store, apples are $1.20 per pound and oranges are $1.80 per pound.
 If the grocer wants to offer a 1.55-pound bag of mixed fruit for $1.62 per pound, how many pounds of apples must he use? 
:
Let a = pounds of apple required
let r = pounds of oranges
:
a + r = 1.55
r = (1.55-a); use this form for substitution
:
1.20a + 1.80r = 1.62(1.55)
replace r with (1.55-a)
1.20a + 1.80(1.55-a) = 1.62(1.55)
1.20a + 2.79 - 1.80a = 2.511
1.20a - 1.80a = 2.511 - 2.79
-.60a = -.279
a = -.279/-.60
a = +.465 lb of apples required
:
:
To check this find the amt of oranges: 1.55-.465 = 1.085 lb of organges
1.2(.465 + 1.8(1.085) = 1.62(1.55)
.558 + 1.953 = 2.511