Take the 2 from the first fraction and multiply is by the denominator (5) to get 10, and then add it to the numerator (2) to get 11. Now you have 11/5
Then, take the 8 and multiply it by 3 to get 24, then add it to the numerator to get 26/3
26 x 11 is 286 and 3 x 5 is 15. So you get 286/15. 286 goes into 15 nineteen times (do 286 divided by 15 and you'll get 19.0666667, so you simply do 19 x 15 and you'll get 285, with 1 left, giving you 19 1/15)
It would be 1/3 because there are three ingredients. Therefore, if he is allergic to one of everything in each category, there are 3/10 things he is allergic to.
