Is there a group G of order 20 such that there exists a surjective homomorphism $\phi: G \rightarrow \mathbb{Z}_{15}$?
I am not sure how to approach this.
$\mathbb{Z}_{15}$ is a cyclic group, and if $\phi$ is surjective then there is $g\in G$ such that $\phi(g)=1$.
By the definition of homomorphism, I get that for all $1\leq m \leq 14$, $\phi(g^m)=m$, and that $\phi(g^{15})=0$.
I know that $G$ doesn't have an element of order $15$, but not sure how to use this.
Hint: $\mathbb{Z}_{15}$ has an element whose order is $3$.