First, multiply the 7 on both sides.


Finally divide by -1 on both sides to get t = -7/15 as your answer.
Answer:
a) X ~ 
b) μ = 100/3
c) 
d) A battery is expected to last 100/3 months (33 months and 10 days approximately).
e) For seven batteries, i would expect them to last 700/3 months (approximately 19 years, 5 months and 10 days).
Step-by-step explanation:
a) The life of a battery is usually modeled with an exponential distribution X ~ 
b) The mean of X is μ = 1/0.03 = 100/3
c) The standard deviation is 
d) The expected value of the bateery life is equal to its mean, hence it is 100/3 months.
e) The expected value of 7 (independent) batteries is the sum of the expected values of each one, hence it is 7*100/3 = 700/3 months.
The purpose of using slang is mostly for social purposes such as:
- It is use as a kind of identity identify for any members of a group.
- It is often used to oppose an already set up authority.
<h3>What is the use of slangs about?</h3>
Slangs is often used in the Sharing and keeping of a constantly altering vocabulary aids.
It is used to show group solidarity and it is often used to include or exclude members.
The common sports slangs are:
- “Game of inches”
- “Lost a step”
- “The ball is in their court”
Learn more about Slangs from
brainly.com/question/476021
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