Question

the price of 5 pens and 4 pencils is 90 rupees .the price of 3 pens and 7 pencils is 65 rupees .what os the price of a pencil?wjat is the price of a pen?define​

Answer 1

Answer :-

Therefore, The Price Of 1 Pen is rupees 16.08

and 1 pencil is rupees 2.4

Step-by-step explanation:

PLEASE REFER TO THE ATTACHMENT......

Answer 2

The Price of the pen is Rs. 16.08

The Price of the pen is Rs. 2.39

Explanation:

Given:

1. The price of 5 pens and 4 pencils is 90 rupees

2. The price of 3 pens and 7 pencils is 65 rupees

To find:

The price of the pen and pencil

Step1:

==> Make an equation from the given condition

==> Let, Pen = x and pencil =y

==> According to condition1

==> 5x + 4y =90 ==> 1

==> According to condition2

==> 3x+7y=65 ==>2

Step2:

==> Using elimination method find the value of x and y

==> Multiply by 3 in the equation 1

==> Multiply by 5 in the equation 2    

==> 15x+12y =270 ==>3

==> 15x+35y =325  

==> changing sign

==> -15x-35y=-325 ==>4

   

Equating equation 3 and 4

   

      15x+12y =270

     -15x-35y=-325

    -------------------------

           - 23y = -55

    --------------------------

==> sign cancels each other

==> 23y=55

==> y=55/23

==> y=2.39 Rs.

Substitute in equation 1

==> 5x + 4y =90

==> y=55/23

==> 5x +4(55/23)=90

==> (115x +220)/23=90

==> 115x +220 = 2070

==> 115x =2070-220

==> 115x = 1850

==> x = 1850/115

==> x = 16.08 Rs.

Price of the pen is Rs. 16.08

Price of the pen is Rs. 2.39