1. There are two candles with different thicknesses. A thin candle is twice as long as a thick candle. It takes 1 hour to light a thin candle and 2 hours to light a thick candle. Once there was a power outage, two such unused candles were lit at the same time. When the phone came in, I found that the remaining length of the two candles was the same. Q:?

According to the problem, the burning speed ratio of thin candle to thick candle is 4: 1.

Let the fine original length be 2 and the coarse original length be 1.

Power outage time t hours 2-4t= 1-t

t= 1/3

Power outage time 1/3 hours

2. Number a 205-page book with 1, 2,3 and ellipsis. After 205, how many times did the number "1" appear?

1~9 1 time

10 ~1911time

20~99 8 times

100~ 199 100+ 1+ 1 1+8= 120

200~205 1 time

Then * * * has1+1+8+120+1=141.