Question 285550
Let {{{r}}} = number Roger sold
Let {{{w}}} = number Will sold
Let {{{j}}} = number Jacob sold
given:
(1) {{{w = r + 9}}}
(2) {{{j = 2r - 3}}}
(3) {{{r + w + j = 66}}}
---------------------
There are 3 equations and 3 unknowns, so it's solvable
Substitute (1) in (3)
(3) {{{r + r + 9 + j = 66}}}
Substitute (2) in (3)
(3) {{{r + r + 9 + 2r - 3 = 66}}}
{{{4r + 6 = 66}}}
{{{4r = 60}}}
{{{r = 15}}}
From (1):
{{{w = r + 9}}}
{{{w = 15 + 9}}}
{{{w = 24}}}
From (2):
{{{j = 2r - 3}}}
{{{j = 2*15 - 3}}}
{{{j = 30 - 3}}}
{{{j = 27}}}
Roger sold 15,  Will sold 24, Jacob sold 27
check:
(1) {{{w = r + 9}}}
{{{24 = 15 + 9}}}
{{{24 = 24}}}
and
(2) {{{j = 2r - 3}}}
{{{27 = 2*15 - 3}}}
{{{27 = 30 - 3}}}
{{{27 = 27}}}
OK