Question 600588
Let {{{ a }}} = Grandson's age now
Let {{{ b }}} = Grandfather's age now
given:
(1) {{{ b = a + 50 }}}
(2) {{{ b - 5 = 6*( a - 5 ) }}}
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Substitute (1) into (2)
(2) {{{ a + 50 - 5 = 6a - 30 }}}
(2) {{{ 6a - a = 50 - 5 + 30 }}}
(2) {{{ 5a = 75 }}}
(2) {{{ a = 15 }}}
and, since,
(1) {{{ b = a + 50 }}}
(1) {{{ b = 15 + 50 }}}
(1) {{{ b = 65 }}}
The Grandfather is 65
check:
(2) {{{ 65 - 5 = 6*( a - 5 ) }}}
(2) {{{ 60 = 6*( 15 - 5 ) }}}
(2) {{{ 60 = 60 }}}
OK