Final answer:
Avery needs to buy 70 kg of milk chocolate and 80 kg of dark chocolate.
Step-by-step explanation:
To solve this problem, we can set up a system of equations. Let's say that the amount of milk chocolate Avery buys is x kg. Since she wants to buy 10 kg more dark chocolate than milk chocolate, the amount of dark chocolate she buys will be x + 10 kg.
The total amount of chocolate she needs is 150 kg, so we can write the equation: x + (x + 10) = 150.
Simplifying this equation, we get 2x + 10 = 150. Subtracting 10 from both sides of the equation, we have 2x = 140. Finally, dividing both sides by 2, we find that x = 70.
Therefore, Avery needs to buy 70 kg of milk chocolate and 70 + 10 = 80 kg of dark chocolate.