Are both of my answers correct? if not explain please.

Write a method named addall that could be placed inside the hashintset class. this method accepts another hashintset as a parameter and adds all elements from that set into the current set, if they are not already present. for example, if a set s1 contains [1, 2, 3] and another set s2 contains [1, 7, 3, 9], the call of s1.addall(s2); would change s1 to store [1, 2, 3, 7, 9] in some order. you are allowed to call methods on your set and/or the other set. do not modify the set passed in. this method should run in o(n) time where n is the number of elements in the parameter set passed in.

How is the number 372 written when expanded out to place values in the base 8 (octal) number system? a. 2 x 4 + 3 x 2 + 4 x 1 b. 3 x 64 + 7 x 8 + 2 x 1 c. 3 x 8 + 7 x 7 + 2 x 6 d. 3 x 100 + 7 x 10 + 2 x 1

How do we use the sumif formula (when dealing with different formats) ?