Word problems confuse me.

THe owner of a fancy food shoppe wants to mix cashews selling at $8/kg and pecans selling at $7/kg. How many kg of each kind of nuts should be mixted to get 8 kg worth $7.25/kg?

1 answer

$8/kg*Xkg + $7kg*Ykg = 7.25/kg*8kg,

Eq1: 8X + 7Y = 58,

Eq2: X + Y = 8,
Multiply Eq2 by -8, add the 2 Eqs and get:
-Y = -6,
Y = 6kgs of pecans.

Substitute 6 for Y in Eq2 :
X + 6 = 8,
X = 2 kgs of cashews.