Question

An orange has 20 fewer calories

Answer 1

Answer:

90 calories in a banana.

Step-by-step explanation:

O = B - 20     where  O is the number calories in an orange and B is a that in  banana.

Also 7B = 9O

From the above   O = 7B / 9 so substituting in the first equation:

7B / 9 = B - 20

7B = 9B - 180

2B = 180

B = 90.