Question

A sum of ₹ 500 is in the form of denominations of ₹ 5 and ₹ 10. If the total number of notes is 90 find the number of notes of each denomination.

Answer 1

Number of ₹ 5 notes = x say. 

Number of ₹ 10 notes = 90 – x 

5x + 10(90 – x) = 500 

5x + 900 – 10x = 500

– 5x = 500 – 900 = – 400 

x = \(\frac{-400}{-5}\)

∴ x = 80 

∴ Number of ₹ 5 notes = 80

Number of ₹ 10 notes 

= 90 – x = 90 – 80 = 10