Question

A number is selected at random from the numbers 3, 5, 5, 7, 7, 7, 9, 9, 9, 9 The probability that the selected number is their average is
(a)$\frac{1}{10}$
(b)$\frac{3}{10}$
(c)$\frac{7}{10}$
(d)$\frac{9}{10}$

Answer 1

SOLUTION :  

The correct option is (b) : 3/10

Given : A number is selected from the numbers 3, 5, 5, 7, 7, 7, 9, 9, 9, 9

Total number of outcomes = 10  

Average of numbers = sum of numbers /  Total numbers

Average of numbers = (3+ 5+5+7+7+7+9+9+9+9) /10  

= 70/10 = 7  

Average of numbers = 7  

Average of numbers 7 is 3 times  

Number of favourable outcomes = 3  

Let E = Event of selecting number is the  average of numbers

Probability (E) = Number of favourable outcomes / Total number of outcomes

P(E) = 3/10

Hence, the probability of selecting number is the  average of numbers , P(E) = 3/10

HOPE THIS ANSWER WILL HELP  YOU…

Answer 2

your correct option is B

B. 3/10