Question 497638
Let {{{f}}} = Father's age
Let {{{s}}} = Son's age
given:
(1) {{{ f = 4s }}}
(2) {{{ f + 6 + s + 6 = 57 }}}
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(1) {{{ s = f/4 }}}
By substitution,
(2) {{{ f + 6 + f/4 + 6 = 57 }}}
Multiply both sides by {{{4}}}
(2) {{{ 4f + 24 + f + 24 = 228 }}}
(2) {{{ 5f = 228 - 48 }}}
(2) {{{ 5f = 180 }}}
(2) {{{ f = 36 }}}
The Father is 36
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check answer:
(1) {{{ s = f/4 }}}
(1) {{{ s = 36/4 }}}
(1) {{{ s = 9 }}}
and
(2) {{{ f + 6 + s + 6 = 57 }}}
(2) {{{ 36 + 6 + 9 + 6 = 57 }}}
(2) {{{ 42 + 15 = 57 }}}
(2) {{{ 57 = 57 }}}
OK