CS$2400$ Assignment$1$ CPU Performance

A processor has three types of instructions $A,B,$ and C $,$ which require $1,2$

and $3$ clock cycles respectively. The instruction flow that generated by the

compiler of this processor for a given program contains $20$ A$-$type, $20$ B$-$

type, and $60$ C$-$type instructions.

What is the CPI $($average cycle per instruction$)$ of this processor to run such

a program?