We are given equation: 15x + 10(2x) + 5(3x) = 30.
Where x represents number of pounds.
Almost cost = $15 per pound.
Therefore, cost of x pounds of almonds = 15*x = 15x .
Walnuts cost = $10 per pound.
We have two parts walnuts.
Therefore, cost of 2 times x pounds of walnuts = 10*(2x).
Raisins cost = $5 per pound.
We are given three parts raisins.
Therefore, cost of 3 times x pounds of raisnis = 5*(3x).
Total money spent = $30.
Let us solve the given equation for x now.
15x + 10(2x) + 5(3x) = 30.
15x + 20x +15x = 30.
Combining like terms, we get
50x = 30.
Dividing both sides by 50, we get
50x/50 = 30/50.
x=0.6
Therefore, number of pounds of Almonds = 0.6 pound.
Walnuts = 2x = 2*0.6 = 1.20 pounds.
Raisins = 3x = 3*0.6 = 1.80 pounds.
Therefore, total number of pounds of trail mix can Blake buy = 0.6 + 1.20 + 1.80 = 3.60 pounds.