A grocer mixes peanuts that cost $2.49 per pound and walnuts that cost $3.89 per pound to make 100 pounds of a mixture that costs $3.19 per pound. how much of each kind of nut is put into the mixture

Let a be the amount of peanuts; and

Let b the amount of walnuts

Equation 1 would be: A + B = 100

249a + 389b = 319 (100)

Equation 2 would be: 249a + 389b = 31900

From equation 1:

a = 100 - b

249 (100 - b) + 389b = 31900

24900 - 249b + 389b = 31900

140b = 7000

b = 50 lbs

then from equation 1:

A + 50 = 100

A = 50 pounds