Question 573418
Let {{{ f }}} = Father's age now
Let {{{ d }}} = Daughter's age now
{{{ f + 30 }}} = father's age 30 yrs from now
{{{ d + 30 }}} = Daughter's age 30 yrs from now
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given:
(1) {{{ f + d = 50 }}}
(2) {{{ 3*( f + 30 ) + d + 30 = 242 }}}
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(1) {{{ d = 50 - f }}}
Substitute (1) into (2)
(2) {{{ 3*( f + 30 ) + 50 - f + 30 = 242 }}}
(2) {{{ 3f + 90 - f + 80 = 242 }}}
(2) {{{ 2f = 242 - 170 }}}
(2) {{{ 2f = 72 }}}
(2) {{{ f = 36 }}}
and, since
(1) {{{ d = 50 - f }}}
(1) {{{ d = 50 - 36 }}}
(1) {{{ d = 14 }}}
I am 36 and my Daughter is 14
check:
(2) {{{ 3*( f + 30 ) + d + 30 = 242 }}}
(2) {{{ 3*( 36 + 30 ) + 14 + 30 = 242 }}}
(2) {{{ 3*66 + 44 = 242 }}}
(2) {{{ 198 + 44 = 242 }}}
(2) {{{ 242 = 242 }}}
OK