A student has some $1 bills and some $5 bills. He has 15 bills totaling $47. How many of each type of bill does he have and what 2 equations using substitutions can be used to solve them?

Hey Joe -- reasoning: $47 means having 2 or 7 or 12 ones ... 2 ones leaves 13 fives

-- too big ... 12 ones leaves 3 fives -- too small ==>

**7($1) + 8($5) = 7+40**:)