2000 AMC 12竞赛试题/第18题
Problem
In year 
, the 
day of the year is a Tuesday. In year 
, the 
day is also a Tuesday. On what day of the week did the 
thday of year 
occur?
Solution
There are either 
or 
days between the first two dates depending upon whether or not year is a leap year. Since 
divides into 
, then it is possible for both dates to be Tuesday; hence year is a leap year and is not a leap year. There are 
days between the date in years 
, which leaves a remainder of 
upon division by . Since we are subtracting days, we count 5 days before Tuesday, which gives us 
.
AEIS在线试听课程
