Question 1010043
Let {{{ a }}} = Peter's age
Let {{{ b }}} = Paige's age
Let {{{ c }}} = Perry's age
Let {{{ d }}} = Pippa's age
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There are 4 unknowns, so you
need 4 equations
(1) {{{ a + b + c + d = 27 }}}
(2) {{{ a = b + 2 }}}
(3) {{{ c = 2b + 3 }}}
(4) {{{ d = c - 11 }}}
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Substitute (3) into (4)
(4) {{{ d = 2b + 3 - 11 }}}
(4) {{{ d = 2b - 8 }}}
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Substitute (2), (3), and (4) into (1)
(1) {{{ b + 2 + b + 2b + 3 + 2b - 8 = 27 }}}
(1) {{{ 6b - 3 = 27 }}}
(1) {{{ 6b = 30 }}}
(1) {{{ b = 5 }}}
and
(2) {{{ a = b + 2 }}}
(2) {{{ a = 5 + 2 }}}
(2) {{{ a = 7 }}}
and
(3) {{{ c = 2b + 3 }}}
(3) {{{ c = 2*5 + 3 }}}
(3) {{{ c = 13 }}}
and
(4) {{{ d = c - 11 }}}
(4) {{{ d = 13 - 11 }}}
(4) {{{ d = 2 }}}
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Peter's age is 7
Paige's age is 5
Perry's age is 13
Pippa's age is 2
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check:
(1) {{{ a + b + c + d = 27 }}}
(1) {{{ 7 + 5 + 13 + 2 = 27 }}}
(1) {{{ 27 = 27 }}}
OK
You can check the other 3 equations