marcodonzelli wrote:
If 6 coins are tossed, how many different coin sequences will have exactly 3 tails, if all tails have to occur in a row?
A. 4
B. 8
C. 16
D. 20
E. 24
All 3 tails have to occur in a row. We can, thus, count the 3 tails as a single item.
This leaves us with 3 coins that show heads. However, the heads can occur in any position, not necessarily in a row.
Thus, the 3 tails (counted as 1 item) and the 3 heads make for 4 items of which the 3 heads are identical; as shown below:
(T T T), H, H, HThus, total number of arrangements = \(\frac{4!}{3!} = 4\)
Answer A _________________
Sujoy Kumar Datta |
GMAT Q51 | CAT 99.98 | Mentor & Coach | IIT (Indian Institute of Technology) alumnus
GMAT Prep - personalized |
GMAT 100 Days prep planhttps://www.linkedin.com/in/sujoy-kumar-datta/
YouTube Channel: https://youtube.com/playlist?list=PLnppbrSFKTsbSGS1MnRaj6seI3RacJUkl
Reviews: 1. https://cubixprep.com/student-reviews/ | 2. https://cubixprep.com/student-results/
Email: sujoy.datta@gmail.com | Skype: sk_datta | Whats-App: +919433063089 | Tele-gram: @Sujoy_Kr_Datta