Question 851773
Let {{{ t }}} = the number of minutes that tests were copied
Let {{{ q }}} = the number of minutes that quizzes were copied
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(1) {{{ 5t + 8q = 167 }}}
(2) {{{ t + q = 25 }}}
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Multiply both sides of (2) by {{{ 5 }}}
and subtract (2) from (1)
(1) {{{ 5t + 8q = 167 }}}
(2) {{{ -5t - 5q = -125 }}}
{{{ 3q = 42 }}}
{{{ q = 14 }}}
and, since
(2) {{{ t + q = 25 }}}
(2) {{{ t + 14 = 25 }}}
(2) {{{ t = 11 }}}
You copied 11 tests and 14 quizzes
check:
(1) {{{ 5*11 + 8*14 = 167 }}}
(1) {{{ 55 + 112 = 167 }}}
(1) {{{ 167 = 167 }}}
OK