Question 937257
If you doubled the number of buses, but kept the ratio
of ( girls ) / ( total students ) = {{{ 3/5 }}}, then you have:
{{{ 5 }}} buses
{{{ (3/5)*5 = 3 }}}
{{{ 3 }}} of the buses needed for just girls
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Now you have to scale this back down by {{{ 1/2 }}}
{{{ (1/2)*3 = 3/2 }}}
1 1/2 buses are needed for just girls
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Suppose there are {{{ 10 }}} students
{{{ (3/5)*10 = 6 }}} girls
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Putting {{{ 6 }}} girls in 1 1/2 buses, I have
{{{ 4 }}} filling 1 bus
{{{ 2 }}} in the {{{ 1/2 }}} bus
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That leaves {{{ 4 }}} boys
{{{ 4 }}} boys fill 1 bus
{{{ 1 + 1/2 + 1 }}} = 2 1/2 buses
OK