I)
Every 8.th voter gets a button:
so a sequence of the voters who receive a button is:
8, 16, 24, 32, .... that is 8*1, 8*2, 8*3, 8*4, .... in general: 8k for some integer k
ii)
Every 10.th voter gets a sticker, so the voters who receive stickers are the :
10, 20, 30, 40, .... voters that is 10*1, 10*2, 10*3, 10*4... in general 10t
for some integer t
iii) what we are looking for is the first number which is 8k and 10t at the same time.
8k=2*2*2k,
10t=2*5t
Thus this number must be divisible by 2*2*2*5*{some positive integer}
the smallest number is when the positive integer is 1, thus the number is
2*2*2*5=8*5=40
Answer: g. the 40th
