Question 468815
Let {{{a}}} = the tunnel's width
Let {{{b}}} = the tunnel's length
given:
(1) {{{ b = 22.5a }}}
(2) {{{ b - 50 = 20a }}}
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Substitute {{{b}}} in (1) for {{{b}}} in (2)
(2) {{{ 22.5a - 50 = 20a }}}
Add {{{50}}} to both sides
(2) {{{ 22.5a = 20a + 50 }}}
Subtract {{{ 20a}}} from both sides
(2) {{{ 2.5a = 50 }}}
(2) {{{ 25a = 500
(2) {{{ a = 20 }}}
And, since
(1) {{{ b = 22.5a }}}
(1) {{{ b = 22.5*20 }}}
(1) {{{ b = 450 }}}
The tunnel is 20 ft wide and 450 ft long
check answer:
(2) {{{ b - 50 = 20a }}}
(2) {{{ 450 - 50 = 20*20 }}}
(2) {{{ 400 = 400 }}}
OK