Question 214858
Given:
(1) {{{x + y + z = 51}}}
(2) {{{y + 5 = z}}}
(3) {{{y - 6 = x/2}}}
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from (3)
(3) {{{2y - 12 = x}}}
Substitute (2) and (3) in (1)
{{{2y - 12 + y + y + 5 = 51}}}
{{{4y - 7 = 51}}}
{{{4y = 58}}}
{{{y = 14.5}}}
(2) {{{y + 5 = z}}}
{{{14.5 + 5 = z}}}
{{{z = 19.5}}}
(3) {{{2y - 12 = x}}}
{{{2*14.5 - 12 = x}}}
{{{x = 29 - 12}}}
{{{x = 17}}}
Xanthe is 17, Yarrow is 14.5, Zeke is 19.5
Check answer:
(1) {{{x + y + z = 51}}}
{{{17 + 14.5 + 19.5 = 51}}}
{{{51 = 51}}}
and
(2) {{{y + 5 = z}}}
{{{14.5 + 5 = 19.5}}}
{{{19.5 = 19.5}}}
and
(3) {{{y - 6 = x/2}}}

{{{14.5 - 6 = 17/2}}}
{{{29 - 12 = 17}}}
{{{17 = 17}}}
OK