<u><em>Answer</em></u>

<u><em>Explanation</em></u>
Based on the given conditions, formulate:: 
Substitute
into
:: 
Rearrange variables to the left side of the equation: 
Calculate the sum or difference: 
Divide both sides of the equation by the coefficient of variable: 
Cross out the common factor: 
It's a proportion.
2 is to x as 15 is to 9, or 2/x = 15/9.
Multiply the means and extremes
15x = 18
divide both sides by 15 to get x by itself.
x = 1.2
ANSWER
0.1
EXPLANATION
We want to estimate the quotient of 1.64 ÷ 22.
To do this, we will approximate the two numbers to whole number and solve it.
It becomes:
2 ÷ 20
That is:
Note: since 2 cannot be divided by 20, we write 0. and add a 0 to the back of 2.
The estimate of the quotient is 0.1.
80:2
80 divided by 2 ... which gets you 40. About 40 miles an hour.
Your ratio: 80:2