An example to the rate `xx` span `=` aggregate, is

speed `xx` time `=` distance.

This is explained in detail.

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A train covers `102`km in `3` hours. What is the speed of the train?

- `34` km/hour
- `34` km/hour
- `102` km/hour

The answer is "`34` km per hour".

Unitary method in Speed-Time-Distance:

The distance traveled in `1` unit time is the speed.

A train covers `102`km in `3` hours.

The speed of the train is `102/3` `=34` km per hour.

How much time does a train, at the speed of `60` km per hour, take to cross `240`km?

- `4` hours
- `4` hours
- `8` hours

The answer is "`4` hours".

Speed `xx` time `=` distance.

Speed and distance are given. Time is to be calculated.

What distance a train at the speed `50` km per hour covers in `7` hours?

- `350` km
- `350` km
- `350` hours

The answer is "`350` km"

Speed `xx` time `=` distance.

Speed and time are given. Distance is to be calculated.

A car takes `3` mins to cross a distance `30` meters. How much distance it would cover if it travels for `22` mins?

- `220` meter
- `220` meter
- `660` meter

The answer is "`220` meter"

Speed `xx` time `=` distance.

Time and Distance are in direct variation.

A car going at the speed `10` meter per second crosses `25` meters in the given time. If the speed is increased to `12` meter per second, what distance it travels in the same time?

- `30` meters
- `30` meters
- `10xx25//12` meter

The answer is "`30` meters"

Speed `xx` time `=` distance.

Speed and Distance are in direct variation.

A car takes `3`mins to cross a bridge at `10` meter per second. What is the time it takes to cross the bridge at `20` meter per second?

- `3` min
- `1.5` min
- `1.5` min

The answer is "`1.5` min"

Speed `xx` time `=` distance.

Speed and time are in inverse variation.

**Problems in Speed-Time-Distance** : Simplify the problem to *speed `xx` time `=` distance*

There are three quantities in the equation. Possible formulation of questions are

• two quantities are given, and the third is asked.

• two quantities are given. Under the condition that one of the given is modified, the changed second is asked. (direct or inverse variation)

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