Answer:
B = 3.75t
Step-by-step explanation:
Given;
initial charge of Arianna's phone = 45%
the charge remaining in Arianna battery = 15%
If after 4hours of leaving her house, the battery had 15% remaining battery life, then the battery is discharging at the rate of ( 15% / 4hours) 3.75% per hour.
Thus, the charge remaining in Arianna's battery after she left her house is given by;
B = 3.75t
where;
t is time in hours
B is the percentage of charge remaining
Answer:
i believe it's 31°. not messing around either
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Answer:
Step-by-step explanation:
This is a Combination (as in permutation vs combination) question the symbol (n r) refers to "n choose r". This is sometimes written as nCr
i.e the question is asking you to find how many combinations each will yield when you chose r items from n item without repetition and order does not matter.
I will only do the first question for you and you can just follow the same steps to solve the rest of the questions.
Recall that

Consider question a) we are given (5 1) or ₅C₁
we can see that n = 5 and r = 1
If we substitute this into the formula:
₅C₁ = (5!) / [ (1!)(5- 1)!]
= (5!) / [ (5- 1)!]
= (5!) / (4!)
= (5·4·3·2·1) / (4·3·2·1)
= 5
hence ₅C₁ = 5