Question

A bill for Rs 40 is paid by means of Rs 5 notes and Rs 10 notes. Seven notes are used in all. If x is the number of Rs 5 notes and y is the number of Rs 10 notes, then 

(a) x + y = 7 and x + 2y = 40 

(b) x + y = 7 and x + 2y = 8 

(c) x + y = 7 and 2x + y = 8 

(d) x + y = 7 and 2x + y = 40

Answer 1

(b) x + y = 7 and x + 2y = 8

Total number of notes = 7 

\(\Rightarrow\)x + y = 7 

Total value of notes = Rs 40 

\(\Rightarrow\)5x + 10y = 40 

\(\Rightarrow\)x + 2y = 8