A one-rupee coin, a two rupee coin, a five rupee coin and a ten rupee coin are tossed simultaneously. Then,…
A one-rupee coin, a two rupee coin, a five rupee coin and a ten rupee coin are tossed simultaneously. Then, the expected value of the sum of the values of coins that show heads up is
8
7
10
9
Solution
Expected value of sum of the value of coins shows head up
$
\begin{aligned}
& =1 \times \frac{1}{2}+2 \times \frac{1}{2}+5 \times \frac{1}{2}+10 \times \frac{1}{2} \\
& =\frac{1+2+5+10}{2}=\frac{18}{2}=9 \\
& \quad[\because \text { Probability of getting head }=1 / 2]
\end{aligned}
$