Weighted Mean

Q.

In a game, the probabilities of winning an amount(x) are given in the table below. The expected payout is the weighted mean of the observations with their probabilities. Find the expected payout.
$\begin{array}{cccccccc}Amount\left(x\right)& 0& 10& 20& 30& 40& 50& 60\\ Probability\left(w\right)& 0.25& 0.2& 0.15& 0.15& 0.1& 0.1& 0.05\end{array}$

1. Rs. 18
2. Rs. 21.5
3. Rs. 24.5
4. Rs. 30