Question

a two digit number is to be formed using the digit 0,1,2,3,4 repetatation is allowed . find the probability that a number so formed is a prime number​

Answer 1

Answer:

5  digits are given

0,1,2,3 and 4

and repetation is allowed

ao the first no can be selected in 4 ways

that is, 1,2,3,4

we will not take 0 as a no can not be used as a unit digit

the se2nd no can be 3 or 1 as 2 4 and 0 always gives composit no

now 21 and 33 are the onle 2 case where this cambination will give a composit no

therefore no of possible 2 digit nos will be = 4 * 2 - 2 = 6

Step-by-step explanation:

Answer 2

S - A two digit no formed by using digits 0,1,2,3,4

Therefore

S ={ 10,20,30,40,11,13,12,14,22,33,44,21,23,24,31,34,32,41,42,43}

n(S) = 20

A - A Prime No Is Formed

Therefore

A={ 13,23,31,11,41,43}

n(A)= 6

By Using Formula

P(A)= n(A)/n(S)

P(A)= 6/20= 3/10........Ans

Therefore the probability is 3/10