First let's find her speed, dividing the number of miles by the amount of time:
[tex]\text{speed}=\frac{15}{3}=5\text{ mph}[/tex]Now, let's calculate the speed for each option:
1) 20 miles in 4 hours
[tex]\text{speed}=\frac{20}{4}=5\text{ mph}[/tex]2) 25 miles in 6 hours
[tex]\text{speed}=\frac{25}{6}=4.17\text{ mph}[/tex]3) 10 miles in 3 hours
[tex]\text{speed}=\frac{10}{3}=3.33\text{ mph}[/tex]4) 5 miles in 1 hour
[tex]\text{speed}=\frac{5}{1}=5\text{ mph}[/tex]So the correct options are 1) and 4).
