Lizzy: Mary does her grocery shopping on Saturday. She does her shopping only at a specific store where she is allowed a credit of $100, which must be paid in full before her next shopping trip. That week she spent the full credit limit and paid $15 of it on Tuesday and $23 of it on Thursday. How much credit will Mary need to pay before her next shopping trip?.
Me: Hmmm, let me think. I think this is the detailed solution:
So far, Mary has paid back $15 + $23 = $38 of the credit. So she still needs to pay $100 - $38 = $62. Final answer: 62.