Social Sciences, asked by jyotikumarimati0145, 9 months ago

कक्षा IX प्र
सॉल्वड पे
1. यदि 37 कलम व 53 पेन्सिल की कुल कीमत ₹ 320 है
जबकि 53 कलम व 37 पेन्सिल की कीमत ₹ 400 है, तो
दो कलम की कीमत होगी
(a) ₹ 6.50
(b) ₹ 1.50
6)₹ 13.00
(d) ₹ 15.00​

Answers

Answered by arunyadav1973
4

Explanation:

let कलम be X

let पेन्सिल be y

by first condition

37x+53y=320...1

by second condition

53x+37y =400...2

let add (1)&(2)

37x+53y=320

+

53x+37y=400

90x+90y=720

90(x+y)=720

(x+y)=720/90

x+y=8...3

lets substract 1 from 2

53x+37y=400

-

37x-53y=-320

16x-16y = 80

16(x-y) = 80

x-y = 80/16

x-y = 5...4

lets add(3)&(4)

x+y = 8

+

x-y = 5

2x = 13

x = 13/2

put value of 'x'in equation (4)

x-y = 5

13/2 - y = 5

13/2 - 5 = y

3/2 = y

(x,y) = (13/2 , 3/2)

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