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
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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