下面是是2012年4月21日的SAT官方每日一题的内容，是关于数学方面的，题型是选择。
SAT官方每日一题之数学---选择：
Mathematics > Standard Multiple Choice
Read the following SAT test question and then click on a button to select your answer.
The sum of the digits of a three-digit number is 12. If the hundreds digit is 3 times the tens digit and the tens digit is 1/2 the units digit, what is the tens digit of the number?
Answer Choices
(A) 2
(B) 3
(C) 4
(D) 6
(E) 9
The correct answer is A
Explanation
If stands for the tens digit, then 3X stands for the hundreds digit and 2X stands for the units digit. Since the sum of the digits is12 , 3X+X+2X=12. Solving this gives .