Question

A coin is tossed 1000 times, if the probability of getting a tail is 3/8, how many times head is obtained?

विकल्प

• 525

• 375

• 625

•  725

Answer 1

The total number of trials is 1000. Let x be the number of times a tail occurs.

Let A be the event of getting a tail.

The number of times A happens is x.

Remember the empirical or experimental or observed frequency approach to probability.

If n be the total number of trials of an experiment and A is an event associated to it such that A happens in m-trials. Then the empirical probability of happening of event A is denoted by P (A) and is given by

` P (A) = m/n`

Therefore, we have` P (A) = x /1000 `

But, it is given that `P(A) = 3/8` . So, we have

` x/1000 = 3/8`

⇒ 8x = 3000

`⇒ x = 3000/8`

⇒ x = 375  

Hence a tail is obtained 375 times.

Consequently, a head is obtained 1000 - 375 = 625 times.