PLEASE I NEED YOUR HELP.

In a detergent shop, one carton of omo contains 10 rolls and one roll contains 5 sachets. If the shop has 10 cartons of omo and a Customer purchased 3 cartons, 2rolls and 1sachet, how many will remain?
The answer will be 6 cartons , 6 rolls and 4 sachets. The questions now is, how did you arrive at the answer. show all working if possible drive a formula that can solve this problem. Please snap your solution and send to 08068025738 via WhatsApp. The first to send a good solution stands a chance of getting (#1500) recharge card. Thanks.