Final answer:
To find the ratio of bananas to oranges in the fruit basket, subtract the number of plums and apples from the total number of fruits. Then, subtract the number of oranges from the total number of oranges and bananas to find the number of bananas. Finally, express the ratio of bananas to oranges.
Step-by-step explanation:
To find the ratio of bananas to oranges, we need to determine the quantities of bananas and oranges in the fruit basket. The total number of fruits in the basket is 18, and we know there are 4 plums and 5 apples. Therefore, the number of oranges and bananas combined is 18 - (4 + 5) = 9.
Given that there are 6 oranges, we can subtract this number from the total number of oranges and bananas to find the number of bananas. Therefore, the number of bananas is 9 - 6 = 3.
The ratio of bananas to oranges is therefore 3:6 or simplified as 1:2.