rounding to the nearest tenth to

242.35 the answer would be: 242.40 we round up the 3 because a 5 is next to it...?

Yes. We round up when the next digit is 5 or more.

Minor correction --

Rounding to the nearest tenth, your answer is 242.4 -- not 242.40.

okay thank you...

You're welcome! If you have any more questions, feel free to ask.