Question

5 pencil and 7 pens together cost rs 50 whearas 7 pencil and 5 pen together cost 46 find the cost of one pencil and that one pen

Answer 1

pencil=x rupees

pen=y rupees  

then       5x+7y=50       (a)

              7x+5y=46       (b)

 7×(5x+7y)=7×50  

35x+49y=350             (1)

 5×(7x+5y)=5×46

35x+25y=230             (2)

(2) - (1)

we get

24y=120

y= 5 rupees (cost of pen )

putting y=5 in  a or b we get

x=3 rs