how do i set this up in system of equation?

A bank teller has 35 bills in $5,$10 and $20 denominations. The toatal value from these bills is $370. The total number of $10 bills and $20 bills is 7 more than the number is $5. How many bills of each denomination does the teller have?

Question

how do i set this up in system of equation?

A bank teller has 35 bills in $5,$10 and $20 denominations. The toatal value from these bills is $370. The total number of $10 bills and $20 bills is 7 more than the number is $5. How many bills of each denomination does the teller have?

anonymous · Answer

the way i read it the number of $10 and $20 are the same, and they are both 7 more than the number of $5
if you call the number of $5 say $x$ then there are  $x+7$ $10s and $x+7$ $20s
add them up and set the result equal to $35$