其它
Think Lab buys $24$ experimental apparatus. But two of the digits of the total price on the invoice are not clear, which only show $\overline{\square 8\square 2}$ dollars. The purchasing agent says the two unclear digits on the invoice are the same. Given that the single price of this kind of apparatus is an integer, how much is it? 
Overseas Competition->Knowledge Point->Number Theory Modules->Factors and Multiples
The number of total price can be divided by $3$ and $8$. It can be divided by $8$ which means the tens digit must be $3$ or $7$. And when the tens digit is $7$, the number can be divided by $3$.  Thus, the total price is $7872$ dollars, and each of them is $328$ dollars. 