Question 1045934
(1) {{{ b = 2a }}}
(2) {{{ c = 3b }}}
(3) {{{ d = (1/2)*c }}}
(4) {{{ a + b + c + d = 480 }}}
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(2) {{{ c = 3*(2a) }}}
(2) {{{ c = 6a }}}
and
(3) {{{ d = (1/2)*c }}}
(3) {{{ d = (1/2)*6a }}}
(3) {{{ d = 3a }}}
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Substitute these results into (4)
(4) {{{ a + b + c + d = 480 }}}
(4) {{{ a + 2a + 6a + 3a = 480 }}}
(4) {{{ 12a = 480 }}}
(4) {{{ a = 40 }}}
and
(1) {{{ b = 2a }}}
(1) {{{ b = 2*40 }}}
(1) {{{ b = 80 }}}
and
(2) {{{ c = 6a }}}
(2) {{{ c = 6*40 }}}
(2) {{{ c = 240 }}}
and
(3) {{{ d = 3a }}}
(3) {{{ d = 3*40 }}}
(3) {{{ d = 120 }}}
Alan made 40 calls
Ben made 80 calls
Chris made 240 calls
Doug made 120 calls
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check:
(4) {{{ a + b + c + d = 480 }}}
(4) {{{ 40 + 80 + 240 + 120 = 480 }}}
(4) {{{ 480 = 480 }}}
OK