Latanya leaves her house at 12:30 p.M. And bikes at 12 mi/h to Marta's house. She stays at Marta's house for 90 minute. Both girls walk back to latanya's house at 2.5 mi/h. They arrive at latanya's house at 3:30 p.M. How far is Marta's house from latanya's house?

Respuesta :

Answer:

Marta's house is 3.10 miles from Latanya's house

Step-by-step explanation:

* Lets explain how to solve the problem

- Latanya leaves her house at 12:30 p.M.

- She bikes at 12 mi/hr to Marta's house

- She stays at Marta's house for 90 minute

- Both girls walk back to latanya's house at 2.5 mi/h

- They arrive at latanya's house at 3:30 p.M.

- We need to know how far is Marta's house from latanya's house

∵ Latanya starts her trip at 12:30 p.M.

∵ She returns her home at 3:30 p.M.

∴ The time of her trip is  → 3:30 - 12:30 = 3 hours

- But she stays at at Marta's house for 90 minutes

∵ 1 hour = 60 minutes

∴ 90 minutes = 90 ÷ 60 = 1.5 hours

∴ The time from her house to Marta's house and from Marta's house

    to her house is → 3 - 1.5 = 1.5 hours

- Assume that the distance from her house to Marta's house is d

  and the time from her house to Marta's house is [tex]t_{1}[/tex],

  the time from Marta's house to her house is [tex]t_{2}[/tex]

∵ Latanya bikes at 12 mi/h to Marta's house

∵ Distance = speed × time

∴ d = 12 × [tex]t_{1}[/tex]

∵ Both girls walk back to latanya's house at 2.5 mi/h

∴ d = 2.5 × [tex]t_{2}[/tex]

- Equate the two expressions of d

∴ 12 [tex]t_{1}[/tex] = 2.5 [tex]t_{2}[/tex] ⇒ (1)

∵ [tex]t_{1}[/tex] + [tex]t_{2}[/tex] = 1.5

- Subtract [tex]t_{1}[/tex] from both sides

∴ [tex]t_{2}[/tex] = 1.5 - [tex]t_{1}[/tex] ⇒ (2)

- Substitute equation (2) in equation (1)

∴ 12 [tex]t_{1}[/tex] = 2.5(1.5 - [tex]t_{1}[/tex])

∴ 12 [tex]t_{1}[/tex] = 3.75 - 2.5[tex]t_{1}[/tex]

- Add 2.5 [tex]t_{1}[/tex] to both sides

∴ 14.5 [tex]t_{1}[/tex] = 3.75

- Divide both sides by 14.5

∴ [tex]t_{1}[/tex] = [tex]\frac{15}{58}[/tex] hour

∴ She spends 15/58 hour to bike to Marta's house

- Lets find d

∵ d = 12 [tex]t_{1}[/tex]

∴ d = [tex]12*\frac{15}{58}=3.10[/tex] miles

* Marta's house is 3.10 miles from Latanya's house

Answer:

Marta's house is 3.10 miles from Latanya's house

Step-by-step explanation: