CameraIcon
CameraIcon
SearchIcon
MyQuestionIcon
MyQuestionIcon
1
You visited us 1 times! Enjoying our articles? Unlock Full Access!
Question

There are 10 white and 10 black balls marked 1,2,3.....10. The number of ways in which we can arrange these balls in a row, in such a way that, neighbouring balls are of different colours is

A
10!9!
No worries! We‘ve got your back. Try BYJU‘S free classes today!
B
20!
No worries! We‘ve got your back. Try BYJU‘S free classes today!
C
(10!)2
No worries! We‘ve got your back. Try BYJU‘S free classes today!
D
2(10!)2
Right on! Give the BNAT exam to get a 100% scholarship for BYJUS courses
Open in App
Solution

The correct option is D 2(10!)2
The black and white balls have to be placed alternately. However, the first ball may be black or white.
So,
Case I 1st ball is black.
CI=10!×10!
Case II 1st ball is white.
CII=10!×10!
So, the total no.=10!×10!+10!×10!
Ans=2(10!)2

flag
Suggest Corrections
thumbs-up
0
Join BYJU'S Learning Program
similar_icon
Related Videos
thumbnail
lock
Permutations
MATHEMATICS
Watch in App
Join BYJU'S Learning Program
CrossIcon