Question

Jason's mom drove at 100 km/h for a

Answer 1

Answer: $0.17\ hours$ or $10\ minutes\ and\ 40\ seconds$

Step-by-step explanation:

 For this exercise you must use the following formula:

$V=\frac{d}{t}$

Where "V" is the speed, "d" is the distance and "t" is the time.

Solving for "t":

$t=\frac{d}{V}$

You know that Jason's mom drove a distance of $160\ km$ at $100\ \frac{km}{h}$. Then, we can say that:

$V_1=100\ \frac{km}{h}\\\\d=160\ km$

Then, the time is:

$t_1=\frac{160\ km}{100\ \frac{km}{h}}\\\\t_1=\frac{8}{5}\ h$

If she had driven $90\ \frac{km}{h}$:

$V_2=90\ \frac{km}{h}\\\\d=160\ km$

 And the time would have been:

$t_2=\frac{160\ km}{90\ \frac{km}{h}}\\\\t_2=\frac{16}{9}\ h$ or

Subtracting those times, you get:

$\frac{16}{9}\ h-\frac{8}{5}\ h=0.17\ h$ or $10\ minutes\ and\ 40\ seconds$