setting up word problems to solve

Question

Alvin is
11
years older than Elga. The sum of their ages is
103
. What is Elga's age?

Answer 1

let A = Alvin's age; and let E = Elga's age; then:  A = E + 11,

and A + E = 103; then (substituting):  (E + 11) + E = 103; 

or 2E + 11 = 103;  or  2E = 103 - 11 = 92;  or E = 46;  A = 46 + 11 = 57