The answer would be 31.
Let's break down the place values of the numbers involved in the number 11.
11
1 = Tens
1
11 = Ones
The problem says a number with 2 more tens. So we have to add 2 to the number in the tens place.
1+2 =3
The number is then 31.
Another way to think about this is 2 tens is equal to 20. So it basically says, what number is 20 more than 11.
20 + 11 = 31