Question 126207
Let x be the pounds of $20 coffee necessary.
.
30*90=2700
x *20=20x
(30+x)*40=1200+40x
.
20x+2700=40x+1200
20x=1500
x=75 lbs.
.
Check:
75+30=105 lbs
75*20=1500
1500+2700=4200
105*40=4200
.
Ed