Jennifer mixes an alloy containing 14% gold with an alloy containing 24% gold to make 100 pounds of an alloy with 18% gold. How many pounds of each kind of alloy did she use?

Question

How many pounds of each kind of alloy did she use?

Answer 1

.24x + .14(100-x) = .18(100)

.24x -.14x = .18(100) - .14(100)

.10x= .04(100) = 4

x = 4/.1 = 40 pounds of 24%

and 100-40 = 60 pounds of 14%

.24(40) + .14(60)= 9.6 + 8.4 = 18 = .18(100)

24 is within 6 of 18

14 is within 4 of 18

6/4 = 60lb/40lb