a.
Out of 15, 6 are green, rest are red.
No. of red apples = 15 - 6 = 9
Ratio of all apples in the basket to red apples
= Total no. of apples : No. of apples that are red
= 15 : 9
= 5 : 3
b.
No. of apples that are green = 6
No. of apples that are red = 9
Ratio of red apples to green apples
= No. of apples that are red : No. of apples that are green
= 9 : 6
= 3 : 2