Answer:
2/3, 3/4, 5/6, 7/8, 8/9, 9/10, etc.
Step-by-step explanation:
1/2 is smaller than 1/3, which is smaller than 3/4, which is in turn smaller than 5/6, and so on.
Well, there are 8 boys and the brother is one of them so 1 is 12.5% of 8 and out of 10 girls, there 1 is the sister and 1 out of 10 is 10%. Now we multiply the percentages to get the answer 1/80