she needs 1/6 almonds , 1/3 walnuts and 1/2 of raisins as a fraction of total trail mix.
So she spends $2.5 on almonds. $5 on walnuts and $10 on raisins (total $15)
so that is 2.5/12 = 0.208 pounds almonds
5 / 10.5 = 0.476 pound walnuts
10/4 = 2.5 pounds raisins
so total wieght of the trail mix is 3.19 pounds