Problema Solution

A bill for $123 was paid with $5 and $1 notes, a total of 59 notes being used. Find how many $5 notes were used.

Answer provided by our tutors

Let $5 note be x and $1 be y.

So 5x+y=123

And

x+y=59

Subtracting last. Equation from previous one we get

4x=64

X=16