Cost Price of An Apple and Carrot = 0.9$
Total Cost of Apples and Carrots = 24.8$
Cost of Equal Number of Carrots and Apples = 24.8 - 6.8$ = 18$
Number of Pairs of Apples and Carrots Britta Buy = 18$/0.9 = 20
(Here I am neglecting the extra carrots)
Hence Number of Apples Britta buy = 20
Hope this helps You!!