Question

Estimate how many times a six-sided dice needs to be rolled to obtain the number 4 twenty times.

Answer 1

Given:

A dice is rolled.

To find:

How many times a six-sided dice needs to be rolled to obtain the number 4 twenty times.

Solution:

We know that, if we roll a dice then the possible outcomes are 1, 2, 3, 4, 5, 6.

Total possible outcomes = 6

So, the probability of getting a 4 in one roll is:

$P(4)=\dfrac{1}{6}$

Let n be the number of times the dice is rolled to obtain the number 4 twenty times. Then,

$\dfrac{1}{6}\times n=20$

$\dfrac{n}{6}=20$

$n=20\times 6$

$n=120$

Therefore, the correct option is C.