General Electric manufactures a decorative Crystal Clear 60-watt light bulb. Suppose that the lifetimes of the light bulbs are approximately normally distributed, with a mean of 1550 hours and a standard deviation of 57 hours. What would be the cutoff value for a light bulb that lasts in the top 10% of all bulbs

The lifetime of bulb should be 1623.074 hours or more to lie in the top 10%.        

Step-by-step explanation:

We are given the following information in the question:

Mean, μ = 1550 hours

Standard Deviation, σ =  57 hours

We are given that the distribution of lifetimes of the light bulbs is a bell shaped distribution that is a normal distribution.

Formula:

We have to find the value of x such that the probability is 0.10

Calculation the value from standard normal z table, we have,  

Thus, the lifetime of bulb should be 1623.074 hours or more to lie in the top 10%.

the distance from any point on the parabola to the focus is the exact same as the distance from that point to the directrix.

if you could provide answer choices that might allow me to answer the question easier if my above answer isn't an option! (:

e) none of the above because the measure of angle cba is 101°