Question 832361
{{{ b/g = 5/6 }}}
Multiply both sides by {{{ 6g }}}
{{{ 6b = 5g }}}
You are given that:
{{{ b = 20 }}}, so
{{{ 6*20 = 5g }}}
{{{ 120 = 5g }}}
{{{ g = 24 }}}
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The class is 
{{{ b + g = 20 + 24 }}}
{{{ b + g = 44 }}}
There are 44 pupils