Question

Form the pair of linear equation in the following problem, and find its solution (if they exist) by the elimination method:

Meena went to a bank to withdraw ₹ 2000. She asked the cashier to give her ₹ 50 and ₹ 100 notes only. Meena got 25 notes in all. Find how many notes of ₹ 50 and ₹ 100 she received.

Answer 1

Let the number of ₹ 50 notes = x

The number of 100 rupees notes = y

According to the condition,

Total number of notes 25

x + y = 25              ...(1)

50x + 100y = 2000  

x + 2y = 40          ...(2)   

Subtracting equation (1) from (2), we get

x + 2y - x - y

y = 40 - 25 

y = 15

Putting y = 15 in (1),

x + 15 = 25 

x = 25 - 15

x = 10

Thus, x = 10 and y = 15

∴ Number of 50 rupees notes = 10 and number of 100 rupees notes = 15