22. 2x - 3 would be the equation, the numbers could be x = 4, then y = 5. The other number would be x = 5 and y = 7
23. First you need to find the difference between 0 secs and 20 sec , which is 37. So the amount lost in 10 secs would be 18.5mm. Then you could multiply this by 3 to find for 30 secs, which is 55.5mm and you subtract 55.5 from 120 which gives 64.5mm.