When ringing up a customers cashier needs 25 seconds to process payment as well as 1 second to scan each item being purchased. How long does it take to ring up a customer with 17 items?

Multiply the amount of seconds to ring up items by the amount of items.

1 × 17 = 17

Now add the amount of seconds to process a payment to the product.

17 + 25 = 42

It takes 42 seconds to ring up a customer with 17 items.

what is a pre-existing condition claus?

means if you're already damaged some way when you take out a medical insurance you will not get full compensation for that injury that you already have.