To find the answer, you have to work backwards. You also have to use PEMDAS. Since she multiplied her answer to get 24, you have to work backwards and divide by 3 first. You will get the number 8 after that because 24/3 is 8. Since she also subtracted 4, you have to work backwards and add 4. That gives you an original number of 12.
In getting the average of all the measurement you give you need first to sum all the measurements and also make sure that you do it properly. Then divide the sum with the number of measurements. By calculating the answer is 10.288
