The answer is 4y + 29
The reason we get this as our answer is because it asks us to add these two expressions. Since we are adding, we can set it up to help us get a feel for what it should look like:
3y+5 + y+24
All we have to do to add these two expressions together is combine like terms and that will give us (3y+y) + (5+24) which is equal to 4y + 29
I hope this helped! :))