Solution:
we are given that
A student has some $1 and $5 bills in his wallet.
Let there x $1 bills and y number of $5 bills.
He has a total of 14 bills that are worth $34.
So we can write
[tex]x+y=14[/tex]
[tex]x+5y=34[/tex]
Now solve these two equations together using substitution as follows
[tex]14-y+5y=34\\ \\ 4y=34-14\\ \\ 4y=20\\ \\ y=5\\ \\ x=14-y=14-5=9\\[/tex]
Hence there are 9 $1 bills and 5 bills are of $5.