The lifetime of a 2-volt non-rechargeable battery in constant use has a normal distribution with a mean of 516 hours and a standard deviation of 20 hours. ninety percent of all batteries have a lifetime less than 541.60 hours.

True

Step-by-step explanation:

Data

mean () = 516 hours

standard deviation () = 20 hours

expected lifetime (X) = 541.6 hours

In the figure attached, standard normal distribution table can be seen. Z is computed as follows:

In table can be seen that the area between 0 and 1.28 is 0.3997, or simply 0.4. The area until Z = 0 is 0.5; so, the total area until Z = 1.28 is 0.9. That means 90% of batteries would have 541.6 lifetime hours.

the smallest possible measurement of the width is 14 feet

step-by-step explanation:

let's assume length of parallelogram is 'l'

width of parallelogram is 'w'

the perimeter of a parallelogram must be no less than 40 feet

so, we get

we are given

length of parallelogram is 6 feet

so,

l=6

we can plug it

now, we can solve for w

subtract both sides by 12

divide both sides by 2

and we get

so,

the smallest possible measurement of the width is 14 feet