How many pounds of chocolate worth $1.5 a pound must be mixed with 10 pounds of chocolate worth 60 cents a pound to produce a mixture worth $1 a pound?

 To find out how many pounds of $1.5 chocolate need to be mixed with the 10 pounds of $0.60 chocolate, we can set up an equation based on the value of the chocolate before and after the mixture.

Let x be the pounds of $1.5 chocolate that we need to mix.

1. The total cost of the x pounds of $1.5 chocolate is $1.5x. 2. The total cost of the 10 pounds of $0.60 chocolate is $0.60 * 10. 3. After mixing the chocolates, we will have (x + 10) pounds of a mixture worth $1 per pound.

The equation based on the total cost before and after mixing is: $1.5x (from the expensive chocolate) + $0.60 * 10 (from the cheaper chocolate) = $1 * (x + 10) (from the mixture)

Let's solve this equation:

$1.5x + $0.60 * 10 = $1 * (x + 10) $1.5x + $6 = $1x + $10 $1.5x - $1x = $10 - $6 $0.5x = $4 x = $4 / $0.5 x = 8

So, 8 pounds of $1.5 chocolate must be mixed with 10 pounds of $0.60 chocolate to make a mixture worth $1 a pound.