Question

Miss teng, a school teacher, usually walks at a speed of 0.5 m/s for y km to reach her school on time. On one cloudy day, she decided to walk the y km at a faster speed of w m/s in case it rained. If she reached her school 5 minutes earlier than usual, calculate y.

Answer 1

`y=(3w)/(10\left(2w-1\right))`

Explanation:

We are given

Miss Teng normal walk:

speed =0.5 m/s

distance traveled =y km =y*1000

now, we can find time

we know

time = distance / speed

`t_1=(1000y)/(0.5)`

`t_1=2000y`

Miss Teng walk on cloudy day:

speed =w m/s

distance traveled =y km =y*1000

now, we can find time

we know

time = distance / speed

`t_2=(1000y)/(w)`

If she reached her school 5 minutes earlier than usual

so,

`t_1-t_2=5* 60 sec`

`t_1-t_2=300`

now, we can plug values

`2000y-(1000y)/(w)=300`

now, we can solve for y

we can multiply both sides by w

`2000yw-(1000y)/(w)w=300w`

`2000wy-1000y=300w`

`1000y\left(2w-1\right)=300w`

`y=(3w)/(10\left(2w-1\right))`