I love these problems, because it's just about reading the question. All you need to do is break it down. What do we know the "sum of" something is? We know that it means addition. What are we adding? "three times a number b and 33". Well, how can we express "three times b"? 3b! Right! Well, we know we're adding that to 33, so you're almost done. Right now you should have 3b+33. And what is 3b+33? at least 33. How can we express "at least"? >=, greater than or equal to, right! Finally, we have our answer. 3b+33>=35.