Multiple choice

Seven coins are tossed simultaneously. Find the probability of getting exactly 4 heads. सात सिक्कों को एक साथ उछाला जाता है। 4 शीर्ष प्राप्त होने की प्रायिकता ज्ञात कीजिये।

  1. 17/64

  2. 35/128

  3. 9/32

  4. 3/8

  5. None of these इनमें से कोई नहीं
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

For 7 coin tosses, P(exactly 4 heads) = C(7,4) × (1/2)⁴ × (1/2)³ = 35 × 1/16 × 1/8 = 35/128. Here C(7,4) = 7!/(4!3!) = 35 represents ways to choose 4 heads from 7 tosses. Each specific outcome has probability (1/2)⁷ = 1/128, so total probability = 35/128.

Keep practicing — related questions