Question

Melissa walks 3 miles to the house of a friend and returns home on a bike. She averages 4 miles per hour faster when cycling than when walking, and the total time for both trips is two hours. Find her walking speed.

Answer 1

Answer:

s₁ = 2 m/s

Step-by-step explanation:

given,

distance between Melissa and friend = 3 mile

walking speed = s₁

bike speed = s₂

total time of the trip = 2 hour

given,

s₂ = s₁ + 4

$time =\dfrac{distance}{speed}$

$t =\dfrac{3}{s_1} +\dfrac{3}{s_2}$

$2 =\dfrac{3}{s_1} +\dfrac{3}{s_1+4}$

2(s₁ +4)s₁ = 3 (s₁ + s₁ + 4)

2 s₁² + 8 s₁ = 6 s₁ + 12

s₁² + s₁ - 6 = 0

s₁² + 3 s₁ - 2 s₁ - 6 = 0

(s₁ + 3) (s₁ -2) = 0

s₁ = -3 , 2

s₁ = 2 m/s

walking speed of the Melissa is s₁ = 2 m/s