Question 17

There are six boxes numbered 1, 2, 3, 4, 5, 6. Each box is to be filled up either with a white ball or a black ball in such a manner that at least one box contains a black ball and all the boxes containing black balls are consecutively numbered. The total number of ways in which this can be done equals.

Solution

Total ways when all 6 boxes have only black balls = 1
Total ways when 5 boxes have black balls = 2
Total ways when 4 boxes have black balls = 3
Total ways when 3 boxes have black balls = 4
Total ways when 2 boxes have black balls = 5
Total ways when only 1 box has black ball = 6
So total ways of putting a black ball such that all of them come consecutively = (1+2+3+4+5+6) = 21

Create a FREE account and get:

All Quant CAT complete Formulas and shortcuts PDF
35+ CAT previous papers with video solutions PDF
5000+ Topic-wise Previous year CAT Solved Questions for Free

CAT Quant Questions | CAT Quantitative Ability

CAT Percentages Questions CAT Averages, Ratio and Proportion Questions CAT Mensuration Questions CAT Quadratic Equations Questions CAT Remainders Questions

CAT DILR Questions | LRDI Questions For CAT

CAT Quant Based LR Questions CAT Special Charts Questions CAT Routes And Networks Questions CAT Coins and Weights Questions CAT 2D & 3D LR Questions

CAT Verbal Ability Questions | VARC Questions For CAT

CAT Vocabulary Questions CAT Miscellaneous Questions CAT Odd One Out Questions CAT Para Jumbles Questions CAT Reading Comprehension Questions

CAT 1990 QA Question

CAT Quant Questions | CAT Quantitative Ability

CAT DILR Questions | LRDI Questions For CAT

CAT Verbal Ability Questions | VARC Questions For CAT

Free Quant Questions

Login to your Cracku account

Hello! 👋

Ready to Unlock Your Success?

Please Enter Your OTP

Please enter the following details

Create a free Cracku account