Question

23. A box contains 20 discs which are numbered from 11 to 30 (11,12,13 .....30).
If one disc is drawn at random from the box, find the probability that it bears
i a number divisible by 7
. a number divisible by 5 or a number greater than 15
V​

Answer 1

Answer:

1) Number divisible by 7= 14,21,28

P(no.divisible by 7)= 3/20

2) A number divisible by 5 = 15,20,25,30

a no. greater than 15= 16,17,18,19,20,21,22,23,24,25,26,27,28,29,30.

( P) = 10/20=1/2...

Answer 2

Step-by-step explanation:      A number is divisible by 7 from   11   to   30   are     14 ,21 , 28

probability of a number is divisible 7 = 3/20

number is divisible by 5 or greater then 15 are

15 ,20 ,30   and  16 to 30

probability  = 4/20 +15/20         ( addition because a  or  b )

                   = 19/20