Alex distributed 57 balloons equally to his 7 friends to fill them with water. He filled the remaining balloons. How many more balloons are filled by his friends compared to him?

The correct option is B 7
Total number of balloons = 57
Number of ballons filled by each of his friends can be obtained by dividing 57 by 7.

Lets apply repeated subtraction here.

57 - 7 = 50
50 - 7 = 43
43 - 7 = 36
36 - 7 = 29
29 - 7 = 22
22 - 7 = 15
15 - 7 = 8
8 - 7 = 1

After distirbuting 1 balloon to each of his friends 8 times, he will left with only 1 balloon.

So he will fill only 1 ballon the remaining one.
His friends will fill 8 balloons.

So the difference
= 8 - 1
= 7