Question 185280
Z's age now = {{{z}}}
Son's age now = {{{s}}}
given:
(1) {{{z = s + 18}}}
(2) {{{z - 1 = 3*(s - 1)}}}
Substitute (1) in (2)
(2) {{{s + 18 - 1 = 3*(s - 1)}}}
(2) {{{s + 17 = 3s - 3}}}
(2) {{{2s  = 20}}}
(2) {{{s = 10}}}
and
(1) {{{z = 10 + 18}}}
(1) {{{z = 28}}}
She is 28 and her Son is 10