Question

A grocer has two kinds of tea, one selling for 80 cents per pound and the other selling for 60 cents per pound. How many pounds of each kind must he use to make 50 pounds of tea that will sell for 74 cents per pound?

Answer 1

Imagine what x is tea grocer selling for 80 cents per pound

y is tea grocer selling for 60 cents per pound

{80x+60y=50*74=3700

{x+y=50 //*60

{80x+60y=3700

-

{60x+60y=3000

20x=700

x=35

y=50-35=15

Answer

There is need to use 35 pounds of 80 cents tea and 15 pounds of the 60 cents tea.

Answer 2

x*80+y*60= 50*74
x +y =50 | * ( -60)

80x + 60y= 50*74
-60x - 60y=-50*60
---------------------------
20x= 50*(74-60)=50*14
x=50*14/20=35 pounds of 80 cents tea
y=50-35=15 pounds of 60 cents tea