Answer:
24
Step-by-step explanation:
if 12 cars are half of his collection, his entire collection is 12(2) which equals 24
(x+6)(x-6) would be the factored form
The first one is 23/30 and the second one is 2 19/24
Average = Mean
To find the mean, add up the numbers and divide it by how many numbers there are.
So,

There are 5 numbers in total.

To do these types of division, ignore the decimal and add a 0 at the end.
So we can do:

And put back the decimal.
Hope this helps :)