Let A represent the ounces of the first alloy.
Let B represent the ounces of the second alloy.
Create a system of equations.
First, for the total desired weight:
A + B = 32
Then for the desired gold concentration:
0.75A + 0.98B = 0.8*32
Solving this system of equations gives us approximately.
A = 25.043, B = 6.957
Check your answer:
25.043 + 6.957 = 32
0.75*25.043 + 0.98*6.957 = 25.6, which is 80% of 32