If a lock requires 3 different digits from 0 to 9, how many different combinatio
Practice Questions
Q1
If a lock requires 3 different digits from 0 to 9, how many different combinations can be formed?
720
1000
900
120
Questions & Step-by-Step Solutions
If a lock requires 3 different digits from 0 to 9, how many different combinations can be formed?
Step 1: Understand that we need to choose 3 different digits from the numbers 0 to 9. This means we have 10 possible digits to choose from.
Step 2: Recognize that the order in which we choose the digits matters because they will form a combination for the lock.
Step 3: Use the formula for permutations to find the number of ways to arrange 3 digits out of 10. The formula is nPr = n! / (n - r)!, where n is the total number of items to choose from, and r is the number of items to choose.
Step 4: In our case, n = 10 (the digits 0 to 9) and r = 3 (the digits we want to choose). So we calculate 10P3.
Step 6: Conclude that there are 720 different combinations of 3 different digits that can be formed.
Permutations – The question tests the understanding of permutations, specifically how to calculate the number of ways to arrange a subset of items from a larger set.
Combinatorial Counting – It also involves combinatorial counting principles, where the order of selection matters since the digits are used in a lock combination.