A fair coin is tossed 4 times. What is the probability of getting exactly 3 heads?
A
1/2
B
1/3
C
1/4
D
1/5
উত্তরের বিবরণ
Question: A fair coin is tossed 4 times. What is the probability of getting exactly 3 heads?
Solution:
For 4 tosses, the total number of possible outcomes is = 24 = 16
The number of ways to choose 3 Heads out of 4 tosses is = 4C3 = 4
∴ Probability of getting exactly 3 heads = 4/16 = 1/4

0
Updated: 3 days ago
A group has 8 men and 7 women. In how many ways can a committee of 5 people be formed if the number of women is at least 3?
Created: 1 week ago
A
785
B
988
C
1281
D
1125
Question: A group has 8 men and 7 women. In how many ways can a committee of 5 people be formed if the number of women is at least 3?
Solution:
Given that,
Total committee size = 5
And for women ≥ 3, possible distributions:
Three ways to formed the committee
1. 3 women + 2 men
2. 4 women + 1 man
3. 5 women + 0 men
Now, 1st case- 3 women + 2 men
Choose 3 women from 7, (7C3) = 35
Choose 2 men from 8, (8C2) = 28
∴ Total ways = 35 × 28 = 980
2nd case- 4 women + 1 man
Choose 4 women from 7, (7C4) = 35
Choose 1 man from 8, (8C1) = 8
∴ Total ways = 35 × 8 = 280
And 3rd case-5 women + 0 men
Choose 5 women from 7, (7C5) = 21
No men to choose
∴ Total ways = 21
∴ Total ways = 980 + 280 + 21= 1281

0
Updated: 1 week ago
কটি ঘড়ি প্রতিদিন ১৮ মিনিট করে পিছিয়ে যায়। কতদিন পর ঘড়িটি আবার সঠিক সময় প্রদর্শন করবে?
Created: 3 weeks ago
A
৩০ দিন
B
৪০ দিন
C
৪৫ দিন
D
৬০ দিন

0
Updated: 3 weeks ago
একটি ছক্কা নিক্ষেপ করলে 2 এর গুণিতক আসার সম্ভাবনা কত?
Created: 4 weeks ago
A
2/3
B
1/2
C
3/4
D
1
সমাধান:
ছক্কার নমুনাক্ষেত্র = {1, 2, 3, 4, 5, 6}
2 এর গুণিতক নমুনা = {2, 4, 6}
∴ 2 এর গুণিতক আসার সম্ভাবনা= 3/6
= 1/2

0
Updated: 4 weeks ago