Question 615570
Let Finn's age now = {{{ f }}}
Let Ellen's age now = {{{ e }}}
{{{ f + 10 }}} = Finn's age 10 years from now
{{{ e - 6 }}} = Ellen's age 6 years ago
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(1) {{{ f + e = 40 }}}
(2) {{{ f + 10 = 4*( e - 6 ) - 1 }}}
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(2) {{{ f + 10 = 4e - 24 - 1 }}}
(2) {{{ 4e - f = 35 }}}
(1) {{{ e + f = 40 }}}
Add the equations
{{{ 5e  = 75 }}}
{{{ e = 15 }}}
and, since
(1) {{{ e + f = 40 }}}
(1) {{{ 15 + f = 40 }}}
(1) {{{ f = 25 }}}
Finn's age now is 25
Ellen's age now is 15