# math

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?

1. 👍 0
2. 👎 0
3. 👁 47
1. cost of a pen --- x
cost of a pencil -- y

2x + 4y ≤ 100

4x + 2y = (2x+4y) + 10
2x - 2y = 10
x-y= 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

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.

1. 👍 0
2. 👎 0
posted by Reiny

## Similar Questions

1. ### Math

Mr Panwar buys pencils at Rs.250 per hundred pencils and sells each at Rs.1.75 find his loss or profit percent

asked by Harmandeep on January 3, 2018
2. ### mathyeshoda

salman purchased 8 wood panels for rupees 1500 each for transporting them to his shop he had to spend rupees 800 he then gave the panels a veneer which cost him rupees 8000 he sold 4 panels for rupees 3200 each calculate his total

asked by cbse 8th on October 14, 2014
3. ### 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

asked by cbse 8th on October 14, 2014
4. ### English grammar

Two hundred rupees (are/ is) are a lot of money. Ali along with his brother ( go / goes) goes to the shop. My aunt or my uncle ( is / are) is expected today.

asked by ENGLISH - RIYA ?????? on September 28, 2014
5. ### 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.

asked by Justice on June 23, 2017
6. ### maths-urgently 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

asked by Anonymous on February 23, 2013
7. ### maths-ARITHMETIC 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

asked by Anonymous on February 24, 2013
8. ### 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

asked by faizanurrahman on March 10, 2014
9. ### Algebra

The Yellow Pencil Company sells the best pencils ever made. If the cost of producing x hundred pencils is given by C x x x ( ) 0.4 29 44 = − + 2 and if the revenue generated from the sale of x hundred pencils is R x x x ( ) 0.6

asked by john on November 24, 2015
10. ### Algebra

The Yellow Pencil Company sells the best pencils ever made. If the cost of producing x hundred pencils is given by C(x)=0.4x^2-29x+44 and if the revenue generated from the sale of x hundred pencils is R(x)=-0.6x^2+19x. Money is in

asked by john on November 24, 2015

More Similar Questions