Answer:
Ethan cycles from home for x km at 9km/h to the MRT station.
He waited for 3 mins before catching the next MRT train.
The MRT train travels at an average speed of 60km/h.
He walks for 1/2km at an average speed of 6km/h before reaching his school.
The distance from his home to the school by the above route is 12km and the total time he spent is 28 mins.
:
(i) Express, in terms of x, the time he spent cycling from home to the MRT station.
time = dist/speed
f(x) = x%2F9
:
(ii) Find the distance travelled by Ethan when he was travelling to school using the MRT
dist by train
d = 12 - x - .5
d = 11.5 - x
(iii) Form an equation in x and solve it.
Subtract the 3 min of waiting, change to hrs: 25/60 = 5%2F12
Write a time equation
bike time + train time + walk time = 5/12 hrs
x%2F9 + %28%2811.5-x%29%29%2F60 + .5%2F6 = 5%2F12
multiply by 180, resulting in
20x + 3(11.5-x) + 30(.5) = 15(5)
20x + 34.5 - 3x + 15 = 75
20x - 3x + 49.5 = 75
17x = 75 - 49.5
17x = 25.5
x = 25.5/17
x = 1.5 km by bike
:
You can confirm this yourself, find the time of each stage of the trip and
the total should be 5/12 hrs which .4167 hrs on a calc
HOPE IT HELP
