So there are 20 eggs total.
If Kyla/Kyle found 1/2 the eggs then she/he found 20/2 = 10 eggs
If Kevin found 1/4 of the eggs then he found 20/4 = 5 eggs
Add the two totals 10+5=15
So 15 out of the 20 were found leaving 5 left to find because 20-15=5
Hope this helps!