Question

mr.X sent his servant to the market to buy some pencils worth Rs.15. the servant dropped 3 pencils on the way, thus making mr.X pay Rs.0.25 per penicl more than the stipulated market price. find the no. of pencils which mr.X has received

Answer 1

mr.x sent his servant to buy pencils be y
total worth= rs.15
cost per pencil = 0.25
n.o of pencils = 15/ 0.25 = 6
as he droped 3 pencils mr.x will receive 3 pencils 

Answer 2

Let Pencils Bought In Rs 15 = a
So the C.P of 1 pencil = Rs 15/a
Pencil Recieved By mr.X = a-3
Price of Each Pencil Which Mr.X has To pay=Rs (15/a-3) 

According To Given Statement

  15     -     15      =     0.25
-------      -------- 
  a-3            a
15 a - 15a +45 =   25
--------------------   ------
      a² - 3a            100
         45            =  1
     -----------          ----
      a² - 3a             4
180 = a² - 3a
a² - 3a - 180 = 0
a² + 12a - 15a - 180 = 0
a(a + 12) - 15(a + 12)= 0
(a - 15)(a + 12) = 0
a = 15 or a = -12
No. of pencils Cane be negative So total No.Of Pencils = 15
But mr.X receives a- 3 pencil
so, 
Total No. Of Pencil Received By Mr.X =  15 - 3
                                                                =  12