Question

A standard pair of six sided dice is rolled. What is the probability of rolling a sum greater than or equal to five? Express your answer as a fraction or a decimal number rounded to four decimal places

Answer 1

There are 6 numbers on each dice, then

The total out come = 6 x 6 = 36

We need to find the sum of 2 numbers greater than or equal to 5

`\begin{gathered} 1+5=6 \\ 1+6=7 \\ 2+3=5 \\ 2+4=6 \\ 2+5=7 \\ 2+6=8 \\ 3+2=5 \\ 3+3=6 \\ 3+4=7 \\ 3+5=8 \\ 3+6=9 \end{gathered}`
`\begin{gathered} 4+1=5 \\ 4+2=6 \\ 4+3=7 \\ 4+4=8 \\ 4+5=9 \\ 4+6=10 \end{gathered}`
`\begin{gathered} 5+1=6 \\ 5+2=7 \\ 5+3=8 \\ 5+4=9 \\ 5+5=10 \\ 5+6=11 \end{gathered}`
`\begin{gathered} 6+1=7 \\ 6+2=8 \\ 6+3=9 \\ 6+4=10 \\ 6+5=11 \\ 6+6=12 \end{gathered}`

The outcomes of a sum greater than or equal to 5 are 29

The probability of getting a sum greater than or equal to 5 is

`P(\ge5)=(29)/(36)`