Question

A local culinary market sells ground sumac for $1.25 per ounce and ground thyme for $1.50 per ounce. You want to make a 25-oz seasoning blend using the two spices that sells for $1.35 per ounce. How much of each spice should you use?

Answer 1

Let
x-------> ounces of ground sumac
y-------> ounces of ground thyme

we know that
x+y=25------> x=25-y------> equation 1
1.25x+1.5y=1.35*25-----> 1.25x+1.5y=33.75-----> equation 2

substitute equation 1 in equation 2
1.25*[25-y]+1.5y=33.75------> 31.25-1.25y+1.5y=33.75
0.25y=2.5
y=10
x=25-y-----> x=25-10-----> x=15

the answer is
15 ounces of ground sumac
10 ounces of ground thyme