Important word problems on Linear Equations in two variables 5
Question for practice
The following questions are more helpful for class tenth students for all boards.
*Questions 5. A person bought two pens for Rs. 480. He sold one at a loss of 15% and the other at a gain of 19%. He found that each pen was sold at the same price. Find the cost price of the each pen.
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*HOTS
Ans.
ReplyDeleteLet cost price of one pen = Rs.x
Let cost price of other pen = Rs.y
x+y = 480 ......(1)
gain of 19% on one pen & loss of 15% on the other ,
therefore, selling price of both is same.
x+19/100 x = y-15/100 y
or 100x+19x/100 = 100y-15y/100
or 119x/100 = 85y/100
or 119x-85y = 0 .....(2)
by elimination from (1) and (2),
x = 200
y = 280
therefore, cost price of one pen = Rs.200
Cost price of other pen = Rs.280
Let cost price of one pen = Rs.x
DeleteLet cost price of other pen = Rs.y
x+y = 480 ......(1)
gain of 19% on one pen & loss of 15% on the other ,
therefore, selling price of both is same.
x+19/100 x = y-15/100 y
or 100x+19x/100 = 100y-15y/100
or 119x/100 = 85y/100
or 119x-85y = 0 .....(2)
by elimination from (1) and (2),
x = 200
y = 280
therefore, cost price of one pen = Rs.200
Cost price of other pen = Rs.280
This comment has been removed by the author.
ReplyDeletelet cp of 1 pen=x and the other pen be y.
ReplyDeletetherefore,x+y=480(1)
sp of 1 pen=x-15x/100
sp of other pen=y+19y/100
sp of each pen is same.
therefore,
x-15x/100=y+19y/100
85x=119y
x=119y/100
putting value of x in (1) we get
y=200
x=280
therefore
cp of 1 pen=Rs.200 and cp of other pen is Rs.280
let CP of 1st pen be x and that of 2nd be y .
ReplyDeleteso , x+y = 480 rs. (1)
x-15/100x = y+19/100y
=> 17x/100 = 119y/100
=> 5x - 7y = 0 (2)
from (1)and (2) , by elimination
y = 200 rs
therefore x = 280 rs
hence CP of 1 pen is rs200 and CP of other pen is rs 280
Let cost price of one pen is Rs x
ReplyDeleteLet cost price of other pen is Rs y
(1).... x+y = 480
gain of 19% on one pen & loss of 15% on the other ,
therefore, sp of both is same.
x+19/100 x = y-15/100 y
or 100x+19x/100 = 100y-15y/100
or 119x/100 = 85y/100
(2)..... 119x-85y = 0
by elimination from (1) and (2),
x = 200
y = 280
therefore, c p of one pen = Rs.200
C p of other pen = Rs.280
let cost of 1st pen = Rs.x
ReplyDelete" " " 2nd pen = Rs.y
So, x + y = 480
=> 5x + 5y = 2400.......(1)
Also, [(100-15)/100]x = [(100+19)/100]y
=> 85x/100 = 119y/100
=> 85x = 119y
=> 85x - 119y = 0
=> 5x - 7y = 0.........(2)
Eliminating (1) and (2) we get
y = 200 and x = 280 !!!
THANKS!!!