The symbol ∩ signifies the intersection of the left operand and the right operand. Here, it means "and", as it often does.
Step-by-step explanation:
The solution to the left inequality is x < -1.
The solution to the right inequality is x > -3.
The intersection symbol (∩) means you are interested in the interval where these solutions overlap—the intersection of the solutions: -3 < x < -1; (-3, -1) in interval notation.
The answer would be 20 because you have 5 blocks that are cut into 1/4. It doesn't say anything about any of the pieces disappearing or being used yet so you multiply 4*5 and then you get the answer.
