Answer:
A. Makes the most sense. If you are using multiplication you'd get 18 1/16
Solution: We are given:

Let
be the weight (oz) of laptop
We have to find 
To find the this probability, we need to find the z score value.
The z score is given below:



Now, we have to find 
Using the standard normal table, we have:

0.9236 or 92.36% of laptops are overweight
Your question seems incomplete :-(
Answer:
B
Step-by-step explanation:
Initial mean = 156, Changed mean = 163.92
So, mean increases. Only condition that satisfies this is B.
Answer:
B
Step-by-step explanation:
multiply 18% and 220 which is 39.6
subtract 39.6 from 220 which is 180.4
simplify