A 5-ringed number lock has 10 digits on each ring. How many attempts at the maximum would have to be made before getting the right number?
Explanation:
A number in each of the 5 rings can be selected in 10 different ways.
∴ Total number of combination possible = 10 × 10 × 10 × 10 × 10 = 105
Here, we don’t have to open the lock, we just have to figure out the right combination of lock.
If we consider that the last combination that we get is the right combination, then the maximum combinations we need to try would be 105 – 1.
∴ Required number of attempts before getting the right combination = 105 – 1
Hence, option (c).
» Your doubt will be displayed only after approval.
Help us build a Free and Comprehensive Preparation portal for various competitive exams by providing us your valuable feedback about Apti4All and how it can be improved.