Question

A man bought pens of varied costs for 1125. The price of the pens were 20
and *25. If he has a total of 50 pens, then the number of pens that costed 20
is​

Answer 1

Answer:

No of pens which cost 20 = x

No of pens which cost 25 = y

20x + 25y = 1125 (1)

x+y = 50

20x + 20y = 1000  (2)

Subtract (2) from (1),

5y = 125

y = 25

x =25

=> the number of pens which cost 20 = 25

Answer 2

Let :

• Number of pens that cost 25 = x
• Number of pens that cost 20 = y

Given :

• Total number of pens = 50
• Total cost of pens = 1125

Solution :

• Total number of pen = number of pen that cost 25 + number of pen that cost 20

=> Total number of pen = x+ y

also given that total number of pen = 50

from this we get

x + y = 50 equation 1

• Total cost of pen = 25x + 20y

also total cost = 1125

from this we get

25x + 20y = 1125 equation 2

Multiplying equation 1 by 20 and subtracting from equation 2

we get

=> 25x + 20y - 20(x+y) = 1125 - 20(50)

=> 25x + 20y - 20x - 20y = 1125 - 1000

=> 5x = 125

=> x = 125/5

=> x = 25

putting value of x in equation 1 , we get;

=> x + y = 50

=> 25 + y = 50

=> y = 50-25

=> y = 25

ANSWER :

• Number of pens that cost 20 = 25