Answer:it’s B (120 succes and 80 failures for khan academy)
Step-by-step explanation: trust me
F(x) = 3x + 1
let f(x) = y
y = 3x + 1
y - 1 = 3x
3x = y - 1
x = (y - 1)/3
From y = f(x), x = f⁻¹(y)
<span>x = (y - 1)/3
</span>
f⁻¹(y) = (y - 1)/3
f⁻¹(7) = <span>(7 - 1)/3 = 6/3 = 2
</span>f⁻¹(7)<span> = 2</span>
7hours > 75 minutes, 60 mins in a hr,
We are given with an initial deposit of $20,000 and a future worth of <span>$35,000. In this case, we are asked for the return of income (ROI) of the investment. in this case, we assume the number of years equal to 1. hence,
</span>$35,000 = <span>$20,000* (1+i) ^1
</span>i or ROI then is equal to 0.75
The exponential distribution is:

where

The probability we want is how likely will a dvd player last more than 8 years, given it has already lasted 5 years
To find this, you use conditional probability.

where A is P(x>8) and B is P(x>5)
To find these probabilities, integrate over the distribution:

Sub into conditional probability formula:

Final Answer: Given a dvd player is more than 5 years old, the probability that it will last another 3 more years is about 54.9%