150/5 = 30$ is the amount of one part. Knowing that, we further know that Ivan has 4 parts and Tanya has 1 part, which is 120$ and 30$, respectively. Due to that, we are now dividing Ivan's amount by Tanya's amount : 120/30 = 4, so Ivan has 4 times more money compared to Tanya. Hope this helps!
