Question 1060399
Let {{{ p }}} = the number of pennies in the 1st jar
Let {{{ n }}} = the number of nickels in the 1st jar
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(1) {{{ 1*p + 5*n = 920 }}} ( in cents )
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And, if the numbers of pennies and nickels are switched,
(2) {{{ 1*n + 5*p = 2680 }}}
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(1) {{{ 1*p + 5*n = 920 }}}
(2) {{{ 5*p + 1*n - 2680 }}}
Multiply both sides of (1) by {{{ 5 }}}
and subtract (2) from (1)
(1) {{{ 5p + 25n = 4600 }}}
(2) {{{ -5p - n = -2680 }}}
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{{{ 24n = 1920 }}}
{{{ n = 80 }}}
and
(1) {{{ p + 5n = 920 }}}
(1) {{{ p + 5*80 = 920 }}}
(1) {{{ p = 920 - 400 }}}
(1) {{{ p = 520 }}}
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There are 520 pennies and 80 nickels in the jar
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check:
(2) {{{ n + 5p = 2680 }}}
(2) {{{ 80 + 5*520 = 2680 }}}
(2) {{{ 80 + 2600 = 2680 }}}
(2) {{{ 2680 = 2680 }}}
OK