Fiona picked a total of => 30 apples


She picks apples that are either red or sweet or both red and sweet, this means she did not pick apples that are not sweet irrespective of the color


Total green apples in the basket = 20 and all the 20 green apples are sweet


Target question => How many sweet red apples are in the basket?


Number of all green apples = 20
Number of all green and sweet apples = 20
Number of all green and not sweet apples = 0
Number of all red apples = 30 - 20 = 10


Statement 1 => of the apples in the basket, 26 apples are sweet
i.e red and sweet apples + green and sweet apples = 26
red and sweet apples + 20 = 26
red and sweet apples = 26 - 20 = 6 apples
Statement 1 is SUFFICIENT

Statement 2 => There are 4 red apples in the basket that are not sweet
Red and sweet apples + red and not sweet apples = total red apples
red and sweet apples + 4 = 10
red and sweet apples = 10 - 4 = 6 apples
Statement 2 is SUFFICIENT

Since each statement alone is SUFFICIENT,
Answer = D