Answer:
[tex]\displaystyle b=0.45\ h[/tex]
[tex]\displaystyle p=0.55\ h[/tex]
Step-by-step explanation:
Cinematics
When an object moves at a constant speed, it can be computed as
[tex]\displaystyle v=\frac{x}{t}[/tex]
Where x is the distance traveled and t the time needed to complete it at the constant speed v
If we wanted to compute t from the equation above, then
[tex]\displaystyle t=\frac{x}{v}[/tex]
Elia rode her bicycle from her house to the beach at 18 km/h and then from the beach to the park at 15 km/h, taking 1 hour in the whole travel, each distance being equal. If we call b as the number of hours it took Elia to ride from her house to the beach, and p the number of hours it took her to ride from the beach to the park, then we can compute
[tex]\displaystyle b=\frac{x}{18}[/tex]
[tex]\displaystyle p=\frac{x}{15}[/tex]
The question doesn't ask for something in particular, so I'm helping you by solving the complete problem. We know the total time is 1 hour, so
[tex]\displaystyle b+p=1[/tex]
Replacing b and p
[tex]\displaystyle \frac{x}{18}+\frac{x}{15}=1[/tex]
Multiplying by 90
[tex]\displaystyle \frac{90x}{18}+\frac{90x}{15}=90[/tex]
Simplifying and solving for x
[tex]\displaystyle 5x+6x=90[/tex]
[tex]\displaystyle 11x=90[/tex]
[tex]\displaystyle x=\frac{90}{11}=8.18\ km[/tex]
We finally compute b and p
[tex]\displaystyle b=\frac{8.18}{18}=0.45\ h[/tex]
[tex]\displaystyle p=\frac{8.18}{15}=0.55\ h[/tex]
