Question

20 tickets, on which numbers 1 to 20 are written, are mixed thoroughly and then a ticket is drawn at random out of them. Find the probability that the
number on the drawn ticket is a multiple of 3 or 7.

[CBSE (Foreign) 2016] ​

Answer 1

Answer:

The probality will be

$\frac{8}{20} (or) \: \frac{4}{10} (or) \: \frac{2}{5}$

Step-by-step explanation:

Given,

There are 20 tickets.

Multiples of 3 between 1 and 20 :- 3, 6, 9, 12, 15, 18.

Multiples of 7 between 1 and 20 :- 7, 14.

Sum of no. of. multiples of 3 and 7:- 8

The probabality will be :-

$probabality = \frac{8}{20} (or) \: \frac{4}{10} (or) \: \frac{2}{5}$

Hope it helps you out......

Answer 2

Answer:

total number of tickets = 20 .

tickets are :-

• 1
• 2
• 3
• 4
• 5
• 6
• 7
• 8
• 9
• 10
• 11
• 12
• 13
• 14
• 15
• 16
• 17
• 18
• 19
• 20.

_______________________________

Now , according to the question :-

● multiple of 3 :- total 6 tickets .

• 3
• 6
• 9
• 12
• 15
• 18

therefore, probability (multiple of 3) =

$\frac{number \: of \: outcomes \: }{toal \: number \: of \: events}$

=

$\frac{6}{20} \: \: \: ans \: .$

______________________________

● multiple of 7 :- 2 tickets .

• 7
• 14

therefore, probability (multiple of 7) =

$\frac{no. \: of \: outcomes \: }{total \: no. \: of \: events \: }$

$= \frac{2}{20} \: ans.$