Question

37 pens and 53 pencils together cost ra 320 while 53 pens and 37 pencils together cost ra 400 find the cost of pen and that of a pencil

Answer 1

Let the cost of pens be x
Let the cost of pencils be y


Equation 1 = 37x+53y=320
Equation 2 = 53x+37y=400
Multiply eq 1 by 53 & eq 2 by 37
Eq 3 = 1961x+2809y=16960
Eq 4 =. 1961x+1369y=14800
Sub eq 3&4
1961x+2809y=16960
-1961x-1369×=-14800

=1440y=2160
y=1.5rs
Cost of pencil = 1.5
Substituting the value of y in eq 1
37x+53(1.5)=320
37x+79.5=320
37x=320-79.5
x=240.5/37
x=6.5
Cost of pen = 6.5 rs