# Question #27312

$15$ one dollar notes, and $5$ five dollar ones.
If $a$ the number of $1 notes and $b$the number of$5 notes, then
$a = 3 b$, since $a$ is three times larger than $b$.
$a + 5 b = 40$, since "$1$ times the number of $1 notes plus $5$times the amount of$5 notes should equal the total amount of money, or ($)40". Subtracting the first equation from the second: $5 b = 40 - 3 b \implies 8 b = 40 \implies b = 5$. Substituting $b = 5$in the first equation, we find $a = 15\$.