There are 5 switches in a board. In these 5 switches 1 is attached with the fan. A person has to sta

M4maths Previous Puzzles

05 Jul 2021 PROBABILITY

There are 5 switches in a board. In these 5 switches 1 is attached with the fan. A person has to start the fan in 2 attempts only. Probability of success will be

OPtion

1) 1/5
2) 2/5
3) 3/5
4) 4/5
5) 1
6) 1/2
7) 1/3
8) 1/4
9) 2/3
10) none of these

Solution

Probability of not succeeding in 1st attempt = 4/5
Probability of not succeeding in 2nd attempt = 3/4
Probability of not succeeding in 1st two attempts = (4/5)*(3/4) = 3/5
Probability of succeeding in 1st two attempts = 1-3/5=2/5

Correct Option: 2 Best Solution (2)