Question 1128829
  The sum of David's and Jim's ages is now 65.
      d + j = 65
      let x = j-d (the difference in their ages)
  When David is as old as Jim is now, twice Jim's age minus David's age at that time will be 110.
 2(j+x) - (d+x)) = 110
2j + 2x - d - x = 110
2j - d + x = 110
replace x with (j-d)
2j - d +(j-d) = 110
3j-2d = 110
Use elimination, multiply the 1st equation by 2
3j - 2d = 110
2j + 2d = 130
-----------------addition eliminates d, find j
5j = 240
j = 240/5
j = 48 yrs is Jim's present age
then
48 + d = 65
d = 65 - 48
d = 17 is David's age
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Check this in the statement
48 - 17 = 31 is the difference in their ages
2(48+31) - (17+31) = 110