Answer:
The combined cost of 1 pound of salmon and 1 pound of swordfish is $16.60
Step-by-step explanation:
Let $x be the cost of 1 pound of salmon.
The swordfish costs $0.20 per pound less than the salmon, then $(x-0.20) is the cost of 1 pound of swordfish.
Melissa buys 2.5 pounds of salmon and pays $2.5x for salmon.
Melissa buys 1.25 pounds of swordfish and pays $1.25(x-0.20) for swordfish.
She pays a total of $31.25, then
Solve this equation.
Costs:
1 pound of salmon - $8.40
1 pound of swordfish - $8.20
Combined - $16.60