A number is chosen at random from 10 to 30 both inclusive. What is the probability that the number is divisible by 3?
A
\(\frac{2}{15}\)
B
\(\frac{1}{10}\)
C
\(\frac{1}{3}\)
D
\(\frac{2}{5}\)
Verified Correct Answer: C.
Step-by-Step Mathematical Solution
Sample space S = {10, 11, 12, ... 30}
Let E denote the event of choosing a number divisible by 3
Then E = {12, 15, 18, 21, 24, 27, 30} and n(E) = 7
Prob (E) = \(\frac{n(E)}{n(S)}\)
Prob (E) = \(\frac{7}{21}\)
Prob (E) = \(\frac{1}{3}\)
Source: Myschool Past Questions Archive (Record #27037)