Probability Question 334
Question: If any four numbers are selected and they are multiplied, then the probability that the last digit will be 1, 3, 5 or 7 is
Options:
A) 4/625
B) 18/625
C) 16/625
D) none of these
Show Answer
Answer:
Correct Answer: C
Solution:
The total number of digits in any number at the unit’s place is 10.
Therefore, $ n(S)=10 $ If the last digit in product is 1, 3, 5 or 7, then it is necessary that the last digit in each number must be 1, 3, 5 or 7. Therefore. $ n(A)=4 $
$ \therefore P(A)=\frac{4}{10}=\frac{2}{5} $
Hence, the required probability is $ {{(2/5)}^{4}}=16/625. $
BETA
