I think I'm not very sure and I don't want you to get it wrong!!!! i think this 21.3in if you are not sure look for more alternatives
My work for your question
Answer:
34
Step-by-step explanation:
First we need to do 2/3*21, which equals 14 as 3 and 21 can be simplified to 1 and 7. 7 * 2/1= 14. Then we add the 20 to 14, 20+14= 34
