One group of 3 numbers has a mean of 10, and a second group of 2 numbers has a mean of 5. Which statements about the mean of all 5 numbers are true? Select all that apply.

توضیح

The groups total 3 lots of 10, which is 30, and 2 lots of 5, which is 10, so all five numbers total 40 and their mean is 40 divided by 5. Averaging the two group means gives 7.5 and would only be right if the groups were the same size, because the larger group of three pulls the combined figure closer to 10.