Question 849369
Let {{{ a }}} = Lukas's age now
Let {{{ b }}} = his grand daughter's age now
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The difference in their age will always be 50 years, so:
(1) {{{ a - b = 50 }}}
(2) {{{ a = 4b + 2 }}}
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(1) {{{ a = b + 50 }}}
Substitute this into (2)
(2) {{{ b + 50 = 4b + 2 }}}
(2) {{{ 3b = 48 }}}
(2) {{{ b = 16 }}}
The grand daughter is 16
check:
(1) {{{ a = b + 50 }}}
(1) {{{ a = 66 }}}
and
(2) {{{ a = 4b + 2 }}}
(2) {{{ 66 = 4*16 + 2 }}}
(2) {{{ 66 = 64 + 2 }}}
(2) {{{ 66 = 66 }}}
OK