If repetition is allowed, there are choices for each entry in the password. So, by the multiplication rule Correct: Your answer is correct. , the number of passwords of length n is . Because passwords may have length 4, 5, or 6, by the addition rule Correct: Your answer is correct. , the total number of passwords consisting of 4, 5, or 6 symbols is 15943750000 Correct: Your answer is correct. .

Answer is in the photo. I couldn't attach it here, but uploaded it to a file hosting. link below! Good Luck!

cutt.ly/4zZs6GM

answer:   28.56 feet (approx)

step-by-step explanation:

since, triangle abc has measure of angle c equal to 55 degrees, measure of angle abc equal to 90 degrees, and length of bc equal to 20 feet.

we have to find out the measurement of segment ab.

therefore, tan 55° =

but bc = 20 feet.

⇒ tan 55 ° =  

⇒ ab = 20 × tan 55 °

⇒ ab = 20 × 1.42814800674

⇒ ab = 28.5629601348   ≈ 28.56 feet

the answer is 40.

proof: