Asked by Anonymous
This is an SAT Question of the Day. 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 over 2 the units digit, what is the tens digit of the number?
The way the question is phrased is very confusing.
The answer choices are:
2
3
4
6
9
Answers
Answered by
Reiny
let the tens digit be x
then the hundreds digit is 3x and
the unit digit is 2x
then x + 3x + 2x = 12
x = 2
check: my number must be 624, all the stated conditions are met
so the correct answer is 2
then the hundreds digit is 3x and
the unit digit is 2x
then x + 3x + 2x = 12
x = 2
check: my number must be 624, all the stated conditions are met
so the correct answer is 2
Answered by
DrBob222
One easy way to solve this is to try the numbers given as choices.
If the number is XYZ, then X+Y+Z=12
We know X=3Y (hundreds digit(X) is 3*tens digit(Y) so X = 3Y.
We also know the tens digit (Y) is 1/2 the units digit(Z) so 1/2*Z = Y which I rearranged to Z = 2Y
Now make a table
X.....Y.....Z......Sum
------------------------
6.... 2 ... 4 ..... 12 and the first try gets it. If Y = 2, then X = 3Y = 3*2 = 6. If Y=2, then Z = 2Y = 4
and 6+2+4=12. Voila!
You can quickly go through the others to see that they won't work.
If Y = 3, then X = 9 and Z can't be a number because we're already at 12.
If Y = 4, then X = 12 and we've exceeded 12.
If Y = any other whole number, then 3*Y exceeds 12. Therefore, the tens digit must be 2. The number is 624. Check my thinking. Check my work.
If the number is XYZ, then X+Y+Z=12
We know X=3Y (hundreds digit(X) is 3*tens digit(Y) so X = 3Y.
We also know the tens digit (Y) is 1/2 the units digit(Z) so 1/2*Z = Y which I rearranged to Z = 2Y
Now make a table
X.....Y.....Z......Sum
------------------------
6.... 2 ... 4 ..... 12 and the first try gets it. If Y = 2, then X = 3Y = 3*2 = 6. If Y=2, then Z = 2Y = 4
and 6+2+4=12. Voila!
You can quickly go through the others to see that they won't work.
If Y = 3, then X = 9 and Z can't be a number because we're already at 12.
If Y = 4, then X = 12 and we've exceeded 12.
If Y = any other whole number, then 3*Y exceeds 12. Therefore, the tens digit must be 2. The number is 624. Check my thinking. Check my work.
Answered by
Anonymous
The explanation said:
If x 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 is 12, 3x + x + 2x = 12. Solving this gives x = 2.
Thank you for your help.
Answered by
nikster
i cant find out what the range is for normal numbers e.g 6 4 8 67 2 3 9 5
There are no AI answers yet. The ability to request AI answers is coming soon!
Submit Your Answer
We prioritize human answers over AI answers.
If you are human, and you can answer this question, please submit your answer.