Question 553491
Let {{{ s }}} = the speed of the bicycle
Let {{{ d }}} = the distance between the towns
given:
{{{ s + 30 }}} = the speed of the car
Equation for bicycle:
(1) {{{ d = s*5.25 }}}
Equation for the car:
(2) {{{ d = ( s + 30 )*1.5 }}}
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(2) {{{ d = 1.5s + 45 }}}
Substitute (1) into (2)
(2) {{{ 5.25s = 1.5s + 45 }}}
(2) {{{ 3.75s = 45 }}}
(2) {{{ s = 12 }}}
{{{ s + 30 = 42 }}}
The car is going 42 mi/hr
check answer:
(1) {{{ d = s*5.25 }}}
(1) {{{ d = 12*5.25 }}}
(1) {{{ d = 63 }}} mi
and
(2) {{{ d = ( s + 30 )*1.5 }}}
(2) {{{ d = 42*1.5 }}}
(2) {{{ d = 63 }}}
OK