How many pounds of $1.60 tea must be added to tea costing $1.80 per pound to make a new mixture of 100 pounds costing $1.75 per pound?

(t * 1.6) + [(100 - t) * 1.8) = 100 * 1.75

solve for t

To find out how many pounds of $1.60 tea must be added, we can use the method of mixture problems.

Let's assume the number of pounds of $1.60 tea to be added is 'x' pounds.

The total cost of the $1.60 tea would then be 1.6x dollars.

We know that the total weight of the new mixture will be 100 pounds, so the weight of the $1.80 tea will be (100 - x) pounds.

The total cost of the $1.80 tea would be (1.8 * (100 - x)) dollars.

To get the final mixture costing $1.75 per pound, the total cost of both teas combined should be equal to the cost per pound multiplied by the total weight. Therefore, we have:

1.6x + 1.8 * (100 - x) = 1.75 * 100

To solve this equation, we can simplify and rearrange:

1.6x + 180 - 1.8x = 175

0.2x = 5

x = 5 / 0.2

x = 25

So, 25 pounds of $1.60 tea must be added to tea costing $1.80 per pound to make a new mixture of 100 pounds costing $1.75 per pound.