Answer:
you ate 23/30 of the cake
Explanation:
if you are trying to add uncommon factors you´ll need to convert them so you can add it.
So first you multiply the numerator and the denominator by 3 so it will be 1*3 and 10*3 that will give you 3/30 and for the other other fraction you will do the same but multiply it by 10. so 2*10 and 3*10 the fraction will now look like, 20/30 now you can add them up. The answer will be 23/30 now only 7/30 of the cake is left.