Answer:
50 pounds
Explanation:
Dan and june mix two kind of feed for pedigreed dogs
Feed A worth is $0.26 per pound
Feed B worth is $0.40 per pound
Let x represent the cheaper amount of feed and y the costlier type of feed
x+y= 70..........equation 1
0.26x + 0.40y= 0.30×70
0.26x + 0.40y= 21.........equation 2
From equation 1
x + y= 70
x= 70-y
Substitutes 70-y for x in equation 2
0.26(70-y) + 0.40y= 21
18.2-0.26y+0.40y= 21
18.2+0.14y= 21
0.14y= 21-18.2
0.14y= 2.8
Divide both sides by the coefficient of y which is 0.14
0.14y/0.14= 2.8/0.14
y= 20
Substitute 20 for y in equation 1
x + y= 70
x + 20= 70
x= 70-20
x = 50
Hence Dan and june should use 50 pounds of the cheaper kind in the mix