Question

A dice was rolled 100 times and the number of times that 6 appeared was noted. If the probability of getting a 6 is $\frac{2}{5}$, how many times did 6 come up?

Answer 1

$$\begin{gathered} P(6appeared)=\frac{\mathrm{Number}\mathrm{of}\mathrm{favour}\text{a}\mathrm{ble}\mathrm{outcomes}}{\mathrm{Total}\mathrm{number}\mathrm{of}\mathrm{outcomes}} \\ \Rightarrow \frac{2}{5}=\frac{\mathrm{Number}\mathrm{of}\mathrm{favour}\text{a}\mathrm{ble}\mathrm{outcomes}}{100} \\ \Rightarrow \mathrm{Number}\mathrm{of}\mathrm{favour}\text{a}\mathrm{ble}\mathrm{outcomes}=\frac{100\times 2}{5}=40 \end{gathered}$$
So, 6 appeared 40 times.