Answer: 60 kg dark chocolate, 40 kg milk chocolate
Step-by-step explanation:
Okie soooo
Let's name the variables (which they did for us lol)
d = kg of dark chocolate and m = kg of milk chocolate
He needs 100 kg of chocolate
d + m = 100
and he wants to spend 1120 when dark chocolate costs $12/kg and milk chocolate costs $10/kg
12d + 10m = 1120
Now we solve the system (I shall use elimination method)
Multiply the first equation my -10
-10(d + m) = (100)(-10)
which becomes
-10d - 10m = -1000
12d + 10m = 1120 (rewrite the second equation)
------------------------- (add the two equations together)
2d = 120
d = 60
now substitute d into either equation
60 + m = 100
m = 40
60 kg dark chocolate
40 kg milk chocolate