8 goes into 153 19 times.
The desired number is the difference between the number of messages sent by the 16th day and the number sent by the 9th day:
... n = t(16) - t(9)
... n = (40×√16) - (40×√9)
... n = 40×(4 - 3) = 40
40 text messages were sent between the ninth and sixteenth day of the month.
Yes, I'm relatively sure any number can be written in scientific notation.
The wind is blowing at the rate of 4 miles per hour
<h3>Speed and distances</h3>
The formula for calculating speed is expressed as:
Speed = Distance/Time
Given the following parameters
Speed of airplane = 18 miles per hour
Speed in wind = 2.2 * 10 = 22 miles/hr
Speed of the wind = 22 - 18
Speed of the wind = 4mi/hr
Hence the wind is blowing at the rate of 4 miles per hour
Learn more on speed here: brainly.com/question/4931057