Question 774683
Let {{{ a }}} = Ana's age now
Let {{{b }}} = Belinda's age now
Let {{{ c }}} = Celina's age now
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(1) {{{ a = b + 10 }}}
(2) {{{ b = c - 5 }}}
(3) {{{ 2a = 3c - 6 }}}
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(2) {{{ c = b + 5 }}}
Plug this result into (3)
(3) {{{ 2a = 3*( b + 5 ) - 6 }}}
(3) {{{ 2a = 3b + 15 - 6 }}}
(3) {{{ 2a = 3b + 9 }}}
Plug (1) into (3)
(3) {{{ 2*( b + 10 ) = 3b + 9 }}}
(3) {{{ 2b + 20 = 3b + 9 }}}
(3) {{{ b = 20 - 9 }}}
(3) {{{ b = 11 }}}
and
(1) {{{ a = b + 10 }}}
(1) {{{ a = 11 + 10 }}}
(1) {{{ a = 21 }}}
and
(2) {{{ c = b + 5 }}}
(2) {{{ c = 11 + 5 }}}
(2) {{{ c = 16 }}}
Ana's age now is 21
Belinda's age now is 11
Celina's age now is 16
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check:
(3) {{{ 2a = 3c - 6 }}}
(3) {{{ 2*21 = 3*16 - 6 }}}
(3) {{{ 42 = 48 - 6 }}}
(3) {{{ 42 = 42 }}}
OK you can check other 2 equations