Answer:
A
Step-by-step explanation:
15 red balls = 15r
50 yellow balls = 50y
Add them together: 15r + 50y
Greater than symbol is >
Since the sum of 15 red and 50 yellow is greater than 400, the resulting equation must be 15r + 50y > 400
(if you're still stuck, consider the greater than symbol as an alligator with the numbers on either side representing a number of fish. The alligator always wants to eat the larger number of fish, so whatever number the mouth is open toward is the larger number)
Consider marking brainliest. I hope this helps :)