maths > commercial-arithmetics

Speed, Time, Distance

    what you'll learn...


An example to the rate × span = aggregate, is
speed × time = distance.

This is explained in detail.

examples in speed

A train covers 102km in 3 hours.

The speed of the train is 34km per hour.

Unitary method in Speed-Time-Distance:
The distance traveled in 1 unit time is the speed.

A train covers 102km in 3 hours.
The speed of the train is 1023 =34 km per hour.

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

Speed × time = distance.

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

time =240/60=4 hours.

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

Speed × time = distance.

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

distance =350km

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

Speed × time = distance.
Time and Distance are in direct variation.

Distance traveled =220m

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?

Speed × time = distance.
Speed and Distance are in direct variation.

The distance traveled =2510×12=30m

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

Speed × time = distance.
Speed and time are in inverse variation.

The time taken =3×1020=1.5min


Problems in Speed-Time-Distance : Simplify the problem to
speed × 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)


The outline of material to learn "commercial arithmetics" is as follows.

Note: Click here for the detailed ouline of commercial arthmetics.

  •   Ratio, Proportion, Percentage

    →   Comparing Quantities

    →   Introduction to Ratio

    →   Ration & Fraction Differences

    →   ProportionsP

    →   Percentages

    →   Conversion to percentage

  •   Unitary Method

    →   Introduction to Unitary Method

    →   Direct Variation

    →   Inverse Variation

    →   DIV Pair

  •   Simple & Compound Interest

    →   Story of Interest

    →   Simple Interest

    →   Compound Interest

  •   Rate•Span=Aggregate

    →   Understanding Rate-Span

    →   Speed • Time=Distance

    →   Work-rate • time = Work-amount

    →   Fill-rate • time = Filled-amount

  •   Profit-Loss-Discount-Tax

    →   Profit-Loss

    →   Discount

    →   Tax

    →   Formulas