Question

$8$ coins are tossed simultaneously. The probability of getting at least 6 heads is

• A. $57/64$
• B. $229/256$
• C. $7/64$
• D. $37/256$

Answer 1

The correct option is D $37/256$

The required probability ${=}^8{C}_6{\left(\frac{1}{2}\right)}^6.{\left(\frac{1}{2}\right)}^2{+}^8{C}_7{\left(\frac{1}{2}\right)}^7\left(\frac{1}{2}\right){+}^8{C}_8{\left(\frac{1}{2}\right)}^8.$ $=\frac{1}{256}(28+8+1)=\frac{37}{256}.$