A store mixes Kentucky bluegrass worth $11 per pound and ryegrass worth $14 per pound. The mixture is to sell for $13 per pound. Find out how much of each should be used to make a 588 pound mixture. How many pounds of the Kentucky bluegrass should be in the mixture?

Answer 1

add up the cost of the parts:

If there are x lbs of bluegrass, then there are 588-x pounds of rye grass, so

11x+14(588-x) = 13*588
x = 196

note that since the expensive grass is $3/lb more than the cheap grass, and the final mixture is $1/lb more expensive, since 1 is 1/3 of 3, 1/3 of the grass is cheap, and 2/3 is expensive.