Let be the set of permutations of whose first term is a prime. If we choose a permutation at random from , what is the probability that the third term is equal to

Step-by-step explanation:

Given

Required

Probability the third term is 3

First, we calculate the possible set.

The first must be prime (i.e. 2, 3 and 5) --- 3 numbers

So, the number of set is:

Next, the number of sets if the third term must be 2

i.e. 1 or 5

---- i.e. remove the already selected first term and the 3rd the compulsory third term

i.e. the digit 2

So

So, the probability is:

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