Join WhatsApp Icon JEE WhatsApp Group
Question 29

Archana has to choose a three-digit code for her bike lock. The digits can be chosen from 1 to 9. To help her remember them, she decides to choose three different digits in increasing order, for example 278. The number of such codes she can choose is


Correct Answer: 84

Solution

Share

Choosing three different digits from the nine digits $$1$$ through $$9$$ uniquely determines their increasing order. Therefore the number of codes is $$\binom{9}{3}=\frac{9\cdot8\cdot7}{3\cdot2\cdot1}=84$$.

Get AI Help

Other Cracku’s Useful Resources:

JEE Questions JEE Question Bank JEE Mains Previous Papers JEE Advanced Previous Papers JEE Study Material PDF JEE Mains Mock Test JEE Advanced Mock Test JEE Daily Target

Free JEE Questions

JEE Physics Questions JEE Maths Questions JEE Chemistry Questions
banner

50,000+ JEE Students Trusted Our Score Calculator

Predict your JEE Main percentile, rank & performance in seconds

Check Your Score Now
Ask AI