4x+8y=40
0.8*8=6.4
4x+6.4=40
40-6.4=33.6
4x=33.6
33.6\4=8.4
X=8.4
If x is the number of berries you can buy with 1 dollar,
1 pound of blueberries = $4.00
x pound of berries = $1.00
Lets set up a proportion- because these are directly proportional- when there is more pounds of berries, it will cost more.

Cross multiply
4x=1
Divide both sides by 4 to isolate x
x=1/4 or $0.25
Y 50 I think it is I am not to sure
3 meters is the same thing as 12/4 meters so divide 12/4 by 3/4 to get 4.