Question

The total cost of 8 pens and 5 pencils is 92
and the total cost of 5 pens and 8 pencils is 77.
heir ages.
Find the cost of 2 pencils and 3 pens.​

Answer 1

Let the cost of pen be x and pencil be y,

ATQ

5x+6y=9                                                               ...(i)

and  

3x+2y-=5                                                             ...(ii)

solving (i) and (ii) by eliminatory method we get;

    5x+6y=9

    3x+2y=5( Multiply by 3)

-> 9x+6y=15       ...(iii)

From (i) and (iii)

   5x  +  6y=   9

   9x  +  6y=  15 

(-)     (-)       (-)

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   4x            =  6

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or x= 1.5

Substituting the value of x in (ii) we get

3(1.5)+ 2y=5

->4.5+2y=5

->2y= 5-4.5

-> y=0.5/2

->y=0.25