You would do 5 times 4 which is 20. then count how many zero's there are and put them after the 20.
Subtract the 15 from the 133
you get 118
divide 29.50 from the 118
you get 4
4 people went to the concert
The number of bacteria is the square of the number of minutes. so after 20 mins, there will be 400 bacteria
√
160
simplifies to 4
√
10
.