Complete question is;
Lucy works for a company that manufactures liquid dyes for fabric. She currently wants to mix up some 23%-concentrated teal dye. She has 16 gallons of 15%-concentrated teal dye, as well as plenty of 25%-concentrated teal dye. How many gallons of the 25%-concentrated teal dye will Lucy need to add to the 15%-concentrated teal dye to make a batch with a concentration of 23%?
Answer:
64 gallons
Step-by-step explanation:
We are given;
Quantity of 15%-concentrated teal dye = 16 gallons
Let the number of gallons of 25%-concentrated teal dye needed to add to make the batch with a concentration of 23% be represented as x.
Thus;
(15% × 16) + (25%)x = 23%(16 + x)
Multiply each term by 100 to give;
(15 × 16) + 25x = 23(16 + x)
240 + 25x = 368 + 23x
Rearranging, we have;
25x - 23x = 368 - 240
2x = 128
x = 128/2
x = 64