The lifetimes of batteries are independent with an exponential distribution with a mean of 84 days. Consider

Question:

The lifetimes of batteries are independent with an exponential with a mean of 84 days. Consider a random selection of 350 batteries. What is the probability that at least 55 of the batteries have lifetimes between 60 and 100 days?
Distribution
The word "distribution" has several meanings in the financial world, most of them pertaining to the payment of assets from a fund, account, or individual security to an investor or beneficiary. Retirement account distributions are among the most...