.
Let d be the distance to the school (in kilometers).
Going at the speed of 2.5 km/h, the student spends hours.
Going at the speed of 3 km/h, the student spends hours.
The difference is 6 + 10 minutes = 16 minutes = of an hour = of an hour.
It gives you the "time" equation
- = .
At this point, the setup is just completed.
To find "d", multiply both sides of the equation (1) by 30. You will get
12d - 10d = 8,
2d = 8
d = 8/2 = 4 kilometers.
ANSWER. The distance to the school is 4 kilometers.
CHECK. = 1.6 hours = 1 hour 36 minutes;
= hours = 1 hour and 20 minutes.
The difference is 16 minutes -- ! Correct !
----------------
Using "time" equation is the STANDARD method of solving such problems.
It is simple, logical, straightforward and economic. Going in this way, you will not make a mistake - the logic of the method
prevents you of making mistakes.
From this lesson, learn on how to write, how to use and how to solve a "time" equation.
To see many other similar solved problems, look into the lessons
- Had a car move faster it would arrive sooner
- How far do you live from school? (*)
- Earthquake waves
- Time equation: HOW TO use, HOW TO write and HOW TO solve it
in this site.
For the TWIN problem, see the lesson (*) in the list.