A boy buys 18 sharpners (brown or white) for Rs.100. For every white sharpner, he pays 1 rupee more than the brown sharpner. What is the cost of white sharpner and how much did he buy?
Option
a) 5,13
b) 5,10
c) 6,10 d
d) None of these

• let boy buys x no. of white sharpeners for (y+1)rs each
  and (18-x) brown sharpeneres at y rs each
  so,
  x*(y+1)+y*(18-x)=100
  => xy+x+18y-xy=100
  => x+18y=100
  
  from above eqns,we see tha value of y should less than 6 & x should less than 18
  
  y=5,x=10 only satisfies these two condn
  
  cost of white sharpner=(y+1)= 6
  no. of white sharpner=x = 10
  
  c) 6,10
• 10 years agoHelpfull: Yes(28) No(0)
• option d... 6*10=60
  remaining brown 5*8=40
• 10 years agoHelpfull: Yes(3) No(1)
• let us check from the answers..
  take option c
  num of white sharpner=10 and its cost is 6
  let us verify that
  from the question we know that total num of sharpners=18
  in that we are assuming that white are 10 from the option
  x+y=18
  10+y=18
  y=8
  to make its sum 100...
  according to given condition 10*6=60 and 8*5=40
  60+40=100
  hence option 3 satisfys the problem
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• Ans will be wednesday.
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• b 5,10
  for 5 brown sharpners he pays 30 i.e., for each 6 rs
  for 10 white sharpners he pays 70 i.e., for each 7 rs
• 10 years agoHelpfull: Yes(0) No(2)
• option c
  10 white sharpner @ of 6 each
  and 8 brown sharpner @ of 5 each
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• Split 18 into 2 parts as 10(white) and 8(brown).Then white sharpner is one rupee more than brown.so take the price of white and brown as 6 and 5.Then we get 10*6 + 8*5=100.So cost of white is 6,no.of white he buys is 10,no.of brown he buys is 8.
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• for option (a)
  5*13+(5-1)*(18-13)=5*13+4*5
  =65+20 =85 (not correct bcoz total cost = 100)
  For option (b)
  5*10+(5-1)*(18-10)=5*10+4*8
  =50+32 =82 (not correct)
  For option (c)
  6*10+(6-1)*(18-10)=6*10+5*8
  =60+40 =100 (correct)
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• asnwser b 5,10
  
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• d. None of these
  
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