You have one type of chocolate that sells for $\$ 1.90 / \mathrm{lb}$ and another type of chocolate that sells for $\$ 2.90 / \mathrm{lb}$. You would like to have 3 tbs of a chocolate mixture that sells for $\$ 2.20 / \mathrm{lb}$. How much of each chocolate will you need to obtain the desired mixture?
You will need
Ibs of the cheaper chocolate
and
tbs of the expensive chocolate.

Step 1 ：We have two types of chocolates, one cheaper and one expensive. We want to mix them to get a new type of chocolate that has a specific price per pound. This is a problem of weighted averages. We can set up a system of equations to solve this problem.

Step 2 ：Let's denote: x as the amount of cheaper chocolate (in lbs) and y as the amount of expensive chocolate (in lbs).

Step 3 ：We know that: The total amount of chocolate is 3 lbs (\(x + y = 3\)) and The total cost of the chocolate is $2.20 per pound (\(1.90x + 2.90y = 2.20 * 3\)).

Step 4 ：We can solve this system of equations to find the values of x and y.

Step 5 ：By solving the equations, we get \(x = 2.1\) and \(y = 0.9\).

Step 6 ：Final Answer: You will need \(\boxed{2.1}\) lbs of the cheaper chocolate and \(\boxed{0.9}\) lbs of the expensive chocolate.