Question

4 red bricks have a mean weight of 5kg

5 blue bricks have a mean weight of 9kg

1 green brick has a weight of 6kg


Donna says, "The mean weight of the ten bricks is less then 7kg"


Is donna correct?

Answer 1

Answer: Donna is wrong. Mean weight is 7.1kg

Explanation:

Calculate the mean for the bricks:

4 bricks have a mean weight of 5kg = 4 * 5

5 bricks have a mean weight of 9kg = 5 * 9

1 green brick is 6kg

= (4 * 5 ) + ( 5 * 9) + 6

= 71kg

Mean = 71 / (4 + 5 + 1)

= 7.1 kg