How to calculate the frequency of the processor given the parameters?

Question

Processors

Consider a processor where half of the instructions are CPI=4 and the other half are CPI=3
(CPI stands for Clocks Per Instruction). At what frequency should the processor run so that the
Pmips parameter has a value of 200 MIPS (on average).
I know the answer is 700 MHz. But how to decide no. Maybe someone has come across something similar.

Answer 1

(3 + 4) / 2 = 3.5 cycles per instruction (average)
200 * 3.5 = 700 MHz