Respuesta :
Answer:
By bike= 4 hours
By walk= 3 hours
Step-by-step explanation:
Given: Sydney travel by bike at 9 mph
Sydney travel by walk at 7 mph.
Total trip time= 7 hours
Distance to bookstore= 57 miles.
Lets assume the time spent travelling by bike be "x".
∴ Time spent travelling by walk is [tex](7-x)[/tex]
Now, lets find the distance travelled on bike and by walk.
we know, [tex]Distance= speed\times time[/tex]
∴ Distance by bike= [tex]9\times x= 9x[/tex]
Distance by walk= [tex]7\times (7-x)[/tex]
Using distributive property of multiplication.
∴ Distance by walk= [tex]49-7x[/tex]
Next, forming an equation for total distance travelled to find x.
⇒ [tex]9x+ (49-7x)= 57\ miles[/tex]
Opening parenthesis
⇒ [tex]9x+49-7x= 57[/tex]
⇒[tex]2x+49= 57[/tex]
Subtracting both side by 49
⇒[tex]2x= 8[/tex]
dividing both side by 2
⇒[tex]x= \frac{8}{2}[/tex]
∴[tex]x= 4\ hours[/tex]
Hence, time spent travelling on bike is 4 hours.
Subtituting the value x to find the time spent travelling by walk.
Times spent travelling by walk= [tex]7-4= 3\ hours[/tex]
hence, time spent travelling by walk= 3 hours
