Question 1034519
Let {{{ b }}} = number of boys
Let {{{ g }}} = number of girls
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(1) {{{ b/g = 7/9 }}}
(2) {{{ b + g = 786 }}}
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Multiply both sides of (1) by {{{ 9g }}}
(1) {{{ 9b = 7g }}}
Divide both sides by {{{ 7 }}}
(1) {{{ g = (9/7)*b }}}
Substitute this result into (2)
(2) {{{ b + (9/7)*b = 786 }}}
Multiply both sides by {{{ 7 }}}
(2) {{{ 7b + 9b = 5502 }}}
(2) {{{ 16b = 5502 }}}
(2) {{{ b = 343.875 }}}
Rounded off, there are 344 boys
and
(1) {{{ g = (9/7)*b }}}
(1) {{{ g = ( 9/7 )*343.875 }}}
(1) {{{ g = 3094.875/7 }}}
(1) {{{ g = 442.125 }}}
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check:
(2) {{{ b + g = 786 }}}
(2) {{{ 343.875 + 442.125 = 786 }}}
(2) {{{ 786 = 786 }}}
and
(1) {{{ b/g = 7/9 }}}
(1) {{{ 343.875/442.125 = 7/9 }}}
(1) {{{ .7777 = .7777 }}}
OK
Since the number of boys and girls do not
come out whole numbers, I suspect the given
data is wrong somehow -either copied wrong
or just wrong as it is given.