Q. How many numbers consisting of 5 digits can be formed in which the digits 3, 4 and 7 are used only once and the digit 5 is used twice?
A) 30
B) 60
C) 45
D) 90
Explanation
(b)
Number of five digit numbers that can be formed by using the digits 3, 4 and 7 and 5 is used twice$= \frac{5!}{2!} = 60$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.