Question 908082
We have 3 lb of 20% alloy
We want to add some 80% alloy to make   62% alloy
0.8*x+0.2*3=0.62(3+x)
0.8*x+0.6=1.86+0.62x
0.8x-0.62x=1.86-0.6
0.18x=1.26
x=7 lb at 80% (5.6) is added to 3 lb at 20%(0.6) to make 62% of 10 lb(6.2)
check
0.8*7+0.2*3=0.62(3+7)
5.6+0.6=0.62(10)
6.2=6.2
ok