Huilan is 14 years older than Thomas:
t = Thomas's age
t+14 = Huilan's age
The sum of their ages is 90:
Solve using basic algebra....
(2) Using much the same calculations, but informally....
(a) Subtract 14 from Huilan's age; then the two are the same age, and the sum of their ages is 90-14 = 76.
(b) Divide by 2 to find that Thomas's age is 76/2 = 38.
(c) Add the 14 years back on to Huilan's age to find that his age is 38+14 = 52.
ANSWER: Thomas is 38; Huilan is 52.
Note that the problem only asks for Thomas's age, so we could stop after step (b).
