The number (in scientific notation) is:

The power of "-4" tells us to move the decimal point 4 places to the left.
So, moving it, the number becomes:
Answer:
48
Step-by-step explanation:
We need to find the multiples of 8
8,16,24,32,40,48
48 is between 45 and 50 so he must have bought 48
72x
That's is the unknown number multiplied by 72.
The answer is H you welcome now probably with the answer for that you would get a 70 or 80