The average height of Ivan, Jackie and Ken is $4 \%$ larger than the average height of Ivan and Jackie. If Ivan and Jackie are each $175 \mathrm{~cm}$ tall, how tall is Ken?
Since Ivan and Jackie are each $175 \mathrm{~cm}$ tall, then their average height is $175 \mathrm{~cm}$.

We are told that the average height of Ivan, Jackie and Ken together is $4 \%$ larger than $175 \mathrm{~cm}$, which equals $1.04 \times 175 \mathrm{~cm}=182 \mathrm{~cm}$.

Since the average height of 3 people is $182 \mathrm{~cm}$, then the sum of their heights is $3 \times 182 \mathrm{~cm}$ or $546 \mathrm{~cm}$.

Since Ivan and Jackie are each $175 \mathrm{~cm}$ tall, then Ken's height is $546 \mathrm{~cm}-2 \times 175 \mathrm{~cm}=196 \mathrm{~cm}$.