Let G = {1, -1, i, -i} be a group with respect to multiplication. What is the order of element i (where i = √-1)?

In standard notation, what is the order of the subgroup ⟨5⟩ ⊕ ⟨3⟩ in the direct sum group Z30 ⊕ Z12?

If G is a non-cyclic group of order 57, then what is the number of elements of order 3 in G?

Let G be a group of order 29. Which of the following statements is true?