Under 45 mins is roughly 16%. This is because 68% of the curve exists within 1 SD of the mean. So 16% must be outside and smaller and 16% outside and larger (on average).
It is impossible to determine how likely you are to find someone with exactly the second amount. However, if you are looking for that or less, you would get 84%
Which page is this in the book
Begin solving like you normally would. Add 2.25 to both sides and subtract 9x from both sides to try getting all x values on one side. However, you will find that after subtracting 9x from both sides, all x values go away, and you end with -2.25=1.6. This is not true (-2.25 is not 1.6), so the answer is no solution. There is no value of x which satisfies that equation.
1. The withdrawals adds up to 291+99+150+12= 552
500-552= -52
2. The bus pass which cost $150.
3.1000-552= $448 left
4.1000-552-300-150=$-2 left. Withdrawal had happened.
The answer is 16 outcomes, there are two possible outcomes per classroom, and there are 8 classrooms