Question 969351
Set Up a ratio:
[ gallons ] / [ gallons ] = [ tbspns ] / [ tbspns ]
{{{ 20 / 50 = 3 / x }}}
{{{ 2 / 5 = 3 / x }}}
{{{ 2x = 3*5 }}}
{{{ 2x = 15 }}}
{{{ x = 7.5 }}}
She should add 7.5 tablespoons to her new aquarium