Ok so the answer in here is 60 grams of the alloy with 10% of titanium needed and 40 grams of the alloy with 25% of titanium are needed.
Let me explain it to you
let x = grams of alloy A and y = grams of alloy B.
x + y = 100
which is
mass of A + mass of B = 100
and
0.15x + 0.20y = 0.17*100
which is
fractionA*massA + fractionB*massB = fractionTotal*massTotal
0.15(100 - y) + 0.20y = 17
15 - 0.15y + 0.20y = 17
0.05y = 2
y = 40 grams
x = 100 - y = 60 grams
