Question

iii) Roohi travels 300 km to her home partly by train and partly by bus. She takes 4
hours if she travels 60 km by train and the remaining by bus. If she travels 100 km
by train and the remaining by bus, she takes 10 minutes longer. Find the speed of
the train and the bus separately.


@Anurag - are noi hogi xD huyi to ak or bana lena xD

@Janvi - hm dekha meine :") chor yesab ​

Answer 1

Solution:-

Let the speed of train and bus be u km/h and v km/h.        

       

According to the question:

               

60/u + 240/v = 4 ... (i)  

               

100/u + 200/v = 25/6 ... (ii)    

             

Putting 1/u = p and 1/v = q in the equations, we get    

             

⇒ 60p + 240q = 4 ... (iii)                  

⇒ 100p + 200q = 25/6                  

⇒ 600p + 1200q = 25 ... (iv)  

               

Multiplying equation (iii) by 10, we get  

               

⇒ 600p + 2400q = 40 .... (v)  

               

Subtracting equation (iv) from (v), we get 1200q = 15                  

⇒ q = 15/200 = 1/80 ... (vi)    

             

Putting equation (iii), we get    

             

⇒ 60p + 3 = 4                  

⇒ 60p = 1                  

⇒ p = 1/60                  

⇒ p = 1/u = 1/60 and q = 1/v = 1/80                  

⇒ u = 60 and v = 80    

             

Speed of train = 60 km/h  

Speed of bus = 80 km/h.

Answer 2

$\huge \bold \blue{Answer࿐}$

Width of rectangle is 25 cm.

Step-by-step explanation:

Given :-

A wire bend in form of square of side 30 cm.

Then wire is again bend in form of rectangle of length 35 cm.

To find :-

Width of the rectangle.

Solution :-

Here, Concept is : If we are bending wire in form of square than again bending it in rectangle. Than, perimeter of square will equal to perimeter of rectangle because we are not increasing length of wire by one measure we are bending it in square and rectangular shape.

So,

Perimeter of square = 4 × side

⟶ Perimeter = 4 × 30

⟶ Perimeter = 120

Thus,

Perimeter of square is 120 cm.

According to concept, Perimeter of square and perimeter of rectangle are equal.

So, Perimeter of rectangle is 120 cm.

Let, Breadth or width or rectangle be x cm.

We know,

Perimeter of rectangle = 2(Length + Breadth)

⟶ 120 = 2×(35 + x)

⟶ 120 = 70 + 2x

\⟶ 120 - 70 = 2x

⟶ 50 = 2x

⟶ 50/2 = x

⟶ x = 25

We take, Width of rectangle be x.

Therefore,

Width of rectangle is 25 cm.