Discussion
The ten’s digit of a two-digit number is twice the unit’s digit. Reversing the digits yields a new number that is 27 less than the original number. Which one of the following is the original number?
*This question is included in Nova Math - Problem Set C: Substitution (Plugging In), question #1
| (A) | 12 |
| (B) | ... |
| (C) | ... |
| (D) | ... |
| (E) | ... |
| (F) | ... |
The solution is
Posted: 11/10/2012 20:59
What is "the I it's digit" referring to in this problem?
Posted: 11/10/2012 21:00
What does the "unit's digit" refer to in this problem?
Posted: 11/11/2012 01:34
Larry, for example, in the number 25, the ten's digit is 2, and the unit's digit is 5.
Posted: 04/14/2013 18:58
You can make problems like this into a system of equations which are easy to solve and give you a definite answer without substitution.
You can see how to do this problem below
You can see how to do this problem below
Posted: 04/16/2013 19:35
Emily H, thanks for your posts and the creative use of your iPhone / iPad to attach the workout. Are you a tutor or a student? Because you definitely know your algebra. The students must decide though, whether solving a system of equations will be faster than substitution in a timed environment.
Posted: 04/16/2013 19:57
I'm a student if student means studying to take the gre. I minored in math. If you figure out how to do the system of equations ahead of time, it will be faster. If math is difficult for someone, substitution will probably be faster.
Posted: 04/16/2013 20:02
So you minored in math. The quantitative section will be a breeze for you, then.