Ex 2.5 Q7 Fractions and Decimals Solution- NCERT Maths class 7

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Question

 Dinesh went from place \(A\) to place \(B\) and from there to place \(C\). \(A\) is \(7.5\,\rm{km}\) from \(B\) and \(B\) is \(12.7\,\rm{km}\) from \(C\). Ayub went from place \(A\) to place \(D\) and from there to place \(C\). \(D\) is \(9.3\,\rm{km}\) from \(A\) and \(C\) is \(11.8\,\rm{km}\) from \(D\).Who travelled more and how much ?

Text Solution

What is known?

Distance between points. Dinesh went from place \(A\) to \(B\) and then \(B\) to \(C\). Ayub went from place \(A\) to \(D\) then \(D\) to \(C\).

What is unknown?

Who travelled more and how much.

Reasoning:

Calculate by all the distance travelled by Dinesh to how much he travelled then calculate distance travel by Ayub.

Steps:

Given

 

Distance travelled by Dinesh from \(A\) to \(B = 7. 5\,\rm{km}\)

And from place \(B\) to place \( C = 12.7 \,\rm{km}\)

\[\begin{align} \therefore \text{Total distance travelled by Dinesh} &= AB+ BC\\&= 7.5\,\rm{km} + 12.7\,\rm{km}\\&= 20.2 \,\rm{km}\end{align}\]

Distance travelled by Ayub from place \(A\) to place \(D = 9.3 \,\rm{km}\)

And from place \(D\) to place \(C = 11.8\,\rm{km}\)

\[\begin{align}\therefore\text{Total distance travelled by Ayub}&= 9.3\,\rm{km} + 11.8 \,\rm{km}\\&= 21.1 \,\rm{km}\end{align}\]

On comparing the total distance travelled by Dinesh and Ayub, we get

\( 21.1\,\rm{km}\)\( >\) \( 20.2\,\rm{km}\)

Distance travelled by Ayub > Distance travelled by Dinesh

\[\begin{align}\therefore \text{Ayub covered more distance by Dinesh is}&= 21.1 -20.2\\&= 0.9 \,\rm{km}\\&= 0.9 × 1000 \,\rm{m}\\&= 900\,\rm{m}\end{align}\]