Question 997599
Let {{{ n }}} = number of nickels
Let {{{ d }}} = number of dimes
Let {{{ q }}} = number of quarters
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(1) {{{ n + d + q = 36 }}}
(2) {{{ d = q + 4 }}}
(3) {{{ n = 2q }}}
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There are 3 unknowns and 3 equations,
so it is solvable
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Substitute (2) and (3) into (1)
(1) {{{ 2q + q + 4 + q = 36 }}}
(1) {{{ 4q + 4 = 36 }}}
(1) {{{ 4q = 32 }}}
(1) {{{ q = 8 }}}
and
(2) {{{ d = q + 4 }}}
(2) {{{ d = 8 + 4 }}}
(2) {{{ d = 12 }}}
and
(3) {{{ n = 2q }}}
(3) {{{ n = 2*8 }}}
(3) {{{ n = 16 }}}
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There are 16 nickels, 12 dimes, and 8 quarters
check:
(1) {{{ n + d + q = 36 }}}
(1) {{{ 16 + 12 + 8 = 36 }}}
(1) {{{ 36= 36 }}}
OK