Okay, so go ahead and make your fraction an improper one. Multiply 5 * 1 and add 2. which gets you 7. So 7/5. The 12 * 3 + 11 so 47. 47/12. Find a like denominator, I'm really lazy, so I just multiply the denominators. 12 * 5 is 60. what ever you have to do to the bottom, you have to do to the top. So the number above the 12 needs to be multiplied by 5 and the number above 5 needs to be multiplied by 5. When you get those numbers, add them together. Then subtract that from 10. What ever you get is how many more liters of water you will need. I don't know what grade you are, so if you need it broken down further, contact me.
