| 
 
 
| Question 888027:   A number consists of two digits whose product is 8.if the digits are interchanged, the resulting number will exceed the original one by 18. find the number.
 solution . let the digits be x and y
 x*y= 8      but if    y*x= original number +18
 now this is the problem , if i put 8 instead of the original number the equation becomes            y*x= 8+18    ,   y*x= 26  ,          x= 26/y
 and if i put it in the other equation ,  26/y*y=8 ! y gets cancelled ?
 
 Answer by MathTherapy(10556)
      (Show Source): 
You can put this solution on YOUR website! A number consists of two digits whose product is 8.if the digits are interchanged, the resulting number will exceed the original one by 18. find the number.
 solution . let the digits be x and y
 x*y= 8      but if    y*x= original number +18
 now this is the problem , if i put 8 instead of the original number the equation becomes            y*x= 8+18    ,   y*x= 26  ,          x= 26/y
 and if i put it in the other equation ,  26/y*y=8 ! y gets cancelled ?
 
 I prefer to name the TENS and UNITS digits, T and U, respectively
 Therefore, TU = 8 ------ eq (i)
 The number is: 10T + U, and the number when the digits are interchanged is: 10U + T
 Note that the ORIGINAL number, 10T + U is SMALLER than the interchanged number. We now have:
 10T + U + 18 = 10U + T
 10T - T + U - 10U = - 18
 9T - 9U = - 18
 9(T - U) = 9(- 2)
 T - U = - 2
 T = U - 2 ------- eq (ii)
 Solve the system to determine T, the TENS DIGIT and U, the UNITS DIGIT. Remember that these values
 MUST be POSITIVE (> 0)
 Then do a check!!
 If you need a complete and detailed solution, let me know!!
 Send comments, “thank-yous,” and inquiries to “D” at MathMadEzy@aol.com.
 Further help is available, online or in-person, for a fee, obviously.
 For FREE info and answers to questions about the ASVAB exam, the NYS 3 – 8 city/state wide exams,GENERAL
 MATH and HOMEWORK QUESTIONS, or MATH QUESTIONS related to the Regents Integrated Algebra,
 Regents Geometry, Regents Algebra 2/Trigonometry, SHSAT, COOP/HSPT/TACHS, PSAT, SAT, ACT, SSAT/ISEE,
 GRE, CLEP, and the TASC/GED, you can visit: http://asvabstudyzone.freeforums.net/.
 | 
  
 | 
 |