Ex.1.1 Q6 Integers - NCERT Maths Class 7

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Question

Rita goes \(20\rm\, km\) towards east from a point \(A\) to the point \(B.\) From \(B\) she moves \(30\rm\, km\) towards west along the same road. If the distance towards east is represented by a positive integer,then how will you represent the distance travelled towards west? By which integer will you represent her final position from \(A?\)

 Video Solution
Integers
Ex 1.1 | Question 6

Text Solution

What is known?

Distance travelled by Rita towards east from point \(A\) and towards west from point \(B\).

What is the unknown?

Final position of Rita from \(A\)

Reasoning:

Distance travelled towards east from point \(A\) (or the highest positive value of the integer) and Distance travelled towards west from point \(B\) (or the lowest negative value of the integer). Find the difference between the two values. 

Steps:

Distance travelled by Rita towards east \(= 20\rm\,km\)

(distance travelled towards east is represented by positive integer)

Distance travelled by Rita towards west \(=\, – \,30\rm\,km\)

(distance travelled towards west is represented by negative integer)

Final position of Rita from A

\[\begin{align} &=[20 +(-30)]\rm{\,km}\\&= (20-30)\rm{km}\\&= -10\rm{\,km}\end{align}\]

Therefore, we will represent her final position from \(A\) by negative integer i.e. \(–10\rm\,km.\)

  
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