Posted by Anonymous on Saturday, May 21, 2011 at 8:32am.
A man buys 2pens and 4 pencils and gives a hundred rupees note to shop keeper . Shopkeeper ask him to pay Rs10 more to take 4pens and 2pencils. If he bought 2pens and 3pencils how much would the man get back from shopkeeper?

math  Reiny, Saturday, May 21, 2011 at 9:28am
cost of a pen  x
cost of a pencil  y
2x + 4y ≤ 100
4x + 2y = (2x+4y) + 10
2x  2y = 10
xy= 5
x = 5+y
then back in 2x+4y<100
or x+2y ≤ 50
5+y + 2y ≤ 50
3y ≤ 45
y ≤ 15
cost of 2 pens and 3 pencils
= 2x + 3y
= 2(5+y) + 3y
= 10 + 5y
there are multiple answers
Make a chart showing
x .. y (2x+4y) (4x+2y) (2x+3y)
20 15  100  110  85 , so change is 15
19 18  94  104  80 , so change is 20
etc.
(If we assume that Rs 100 was the exact amount for 2pens and 4 pencils, then
20, 15 is the correct answer.)
e.g.
If he bought 2 pens at 20 and 4 pencils at 15
cost would be 100
Had he bought 4 pens and 2 pencils, cost would be 110 which is 10 more as stated,
so cost of 2 pens and 3 pencils is 85, resulting in change of 15
the same can be done for each of the entries in the chart.
Answer This Question
Related Questions
 math  A lady buys goods worth Rs.200 from a shop. (shopkeeper selling the goods...
 math  a shopkeeper bought some eggs at rupees 3 each.20 of them were broken ...
 mathsARITHMETIC PROGRESSIONS  A person buys a refrigerator for rupees 12000. ...
 mathsurgently needed  A person buys a refrigerator for rupees 12000. He pays ...
 b.mathematics  a shopkeeper allows a discount of 15% on his shop. how much ...
 math  John and Smith went to a stationery shop. John bought 6 pens, 4 pencils ...
 math school g  salman purchased 8 wood panels for rupees 1500 each for ...
 math usha kk  a refrigerator is marked at rupees 14500 if 16%vat is charged ...
 Math  Mr.Chan bought some pencils for a group of students. If he gives them 2 ...
 math  Mr. Smith buys pencils at Rs 250 per hundred and sells each at Rs 1.75....
More Related Questions