For a certain type of computers, the length of time between charges of the battery is normally distributed with a mean of 50 hours and a standard deviation of 15 hours. Write down the function, draw...

For a certain type of computers, the length of time between charges of the battery is normally distributed with a mean of 50 hours and a standard deviation of 15 hours. Write down the function, draw bell-shaped curve & calculate the:

a)Area between 50 and 70 hours.

b)Area above 40 hours.

c)X value that has 28% area above it.

d)X value that has 60% area below it.