Question

Three digit numbers formed by using digits 0, 1, 2 and 5 (without repetition) are written on different slips with distinct numbers on each slip, and put in a bowl. One slip is drawn at random from the bowl, the probability that slip bears a number divisible by ‘5’ is​

Answer 1

Answer:

$\huge\bf\underline{\underline{Solutions}}$

There are 4 group of three digits and that is (0,1,2),(0,1,5),(0,2,5),(1,2,5)

The three digit numbers formed by

(0,1,2),(0,1,5),(0,2,5)

groups are 12 (4 for each). 

The three digit numbers formed by (1,2,5) group is 6 

So, sample space S={120,201,102,210,150,105,501,510,250,520,205,502,125,152,521,512,251,215}

n(S)=18

Let A be the event of getting number divisible by 5

So, A= {120,210,150,510,105,250,520,205,125,215}

∴ n(A)=10

$∴ P(A)= \frac{n(</p><p>A)}{n(S)} = \frac{10}{8} = \frac{5}{8}$

So, the answer is ⅝