Minus 3y both sides
2y-6=-20
add 6 to both sids
2y=-14
divide 2
y=-7
Answer:
a. P(X ≤ 5) = 0.999
b. P(X > λ+λ) = P(X > 2) = 0.080
Step-by-step explanation:
We model this randome variable with a Poisson distribution, with parameter λ=1.
We have to calculate, using this distribution, P(X ≤ 5).
The probability of k pipeline failures can be calculated with the following equation:

Then, we can calculate P(X ≤ 5) as:

The standard deviation of the Poisson deistribution is equal to its parameter λ=1, so the probability that X exceeds its mean value by more than one standard deviation (X>1+1=2) can be calculated as:

<span>Amanda has 26 nickels and dimes.
We shall call nickels x and dimes y.
We can write the following equations:
x = 3y -2 or -x +3y = 2
x + y = 26
We can cancel out the x to give 4y = 28 or y = 7
If there are 26 coins in total and 7 of them are dimes then there must be 19 nickels.
The number of nickels (19) is two fewer than three times the number of dimes ( 3(7) - 2 = 19).</span>