Answer:
20
Explanation:
When we round to the nearest ten, we will round up to a number that has a zero in the ones place but we have to look at the number in the ones place before we round to determine the number in the tens place. The rule is if the number in the place before the place we need to round (in this case the ones place would be what we look at to determine the rounded tens place) 1-4 is going to round down, keeping the tens place the same and the ones place goes to zero, and if the ones number place is 5-9 then we round up, bringing the ones to zero and the tens up by one tens place.