math
posted by Anonymous .
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?

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.
Respond to this Question
Similar Questions

mathsurgently needed
A person buys a refrigerator for rupees 12000. He pays rupees 6000 in cash and agrees to pay the balance in 12 annual instalments of rupees 500 each. If the rate of interest is 12% and he pays it with instalments on the unpaid amount, … 
mathsARITHMETIC PROGRESSIONS
A person buys a refrigerator for rupees 12000. He pays rupees 6000 in cash and agrees to pay the balance in 12 annual instalments of rupees 500 each. If the rate of interest is 12% and he pays it with instalments on the unpaid amount, … 
b.mathematics
a shopkeeper allows a discount of 15% on his shop. how much money can a man save if he buys a bag costing rs2500, a shaving set costing rs890 and iron costing rs 2800? 
math
A lady buys goods worth Rs.200 from a shop. (shopkeeper selling the goods with zero profit) .. The lady gives him 1000 rs note. The shopkeeper gets the change from the next shop and keeps 200 for himself and returns Rs.800 to the lady. … 
math school g
salman purchased 8 wood panels for rupees 1500 each for transporting them to his shop he had spend rupees 800 he then gave the panels a veneer wich cost him rupees 8000 he sold 4 panels for rupees 3200 each calculate his total profit … 
math usha kk
a refrigerator is marked at rupees 14500 if 16%vat is charged find the total amount that she will have to pay to the shopkeeper 
math
John and Smith went to a stationery shop. John bought 6 pens, 4 pencils and 3 erasers. Smith bought 3 pens, 8 pencils and 6 erasers and spent 20% more than John. What percentage money did John spend on pens? 
math
a shopkeeper bought some eggs at rupees 3 each.20 of them were broken while the rest were sold at 4 rupees each.if he made a profit of 20%,find how many eggs he bought 
Math
Mr.Chan bought some pencils for a group of students. If he gives them 2 pencils each, he will have 10 pencils left. If he gives them 3 pencils each, he will have none left. How many students are in the group? 
math
James has 1800sh to buy pencils. There two types of pencils, cheap and expensive The prices differ for 40 sh. If he buys cheap pencils he gets 12 more. What is price of the pencils.