Answer:
Given,
2 cups of yellow paint is needed for every 3 cups of red paint to make a batch of orange paint,
So, the ratio of yellow paint and red paint in a batch of orange paint = 2 : 3
Make two number lines,
First one represents the multiple of 2 and second one represents the multiples of 3,
By the double number line ( shown below ),
It is clear that,
For 3 batches of orange paint, 6 cups of yellow paint and 9 cups of red paint are needed.