Question

37 pens & 53 pencils together cost rs320 while 53 pens & 37 pencils together cost 400 . find the cost of pen & that of a pencil.

Answer 1

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Answer 2

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Answer:IN Ist CASE

Number of pens = 37

Number of pencils = 53

Together cost = Rs 320

IN IInd CASE

Number of pens = 53

Number of pencils = 37

Together cost = Rs 400

To find : The cost of a pen and that of a pencil.

Let the cost of the pen be Rs " x "and

That of pencil be Rs " y ".

Then, According to given question

37x + 53y = 320  --------- ( i )

and, 53x + 37y = 400  ------ ( ii )

Now we are , Adding the equations (i) and (ii)

Then we get :

90x + 90y = 720 ⇒ x + y = 8    ----- ( iii )

Now subtract eq ( i ) and ( ii ) ,

We get :

16x - 16y =  80 ⇒ x - y = 5   ----------- ( iv )

Add equation  ( iii ) and  ( iv )

We get :

2x = 13 ⇒ x = 6.5

Subtract x = 6.5 in equation ( iii ) ,

We get :

y = ( 8 - 6.5 )

Answer

4.0/5

74

Let the number of pens be 'x' and the number of pencils be 'y'

Therefore 37x + 53y = 320 ---1

53x +37y = 400 ----2

Now, adding both the equations,

90x + 90y = 720 (dividing the whole equation by 90 )

X + y = 8 -----3

Now subtracting both the euations,

-16x +16y = -80 (dividing the equation by 16)

-x +y = -5 ---4

Adding 3 and 4

2y=3

Y=3/2

Y= 1.5rs

Therefore x = 13/2

X=6.5rs

Step-by-step explanation:

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