Let x = the numbers of girls
thus
the numbers of boys = 2x
x + 2x = 27
3x = 27
x = 9
2x = 2 . 9 =18
girls = 9 & boys = 18
Let x be the capacity of the tank then
3x/4-x/8 =15,
then x=24, so so far it has 3/4 *24 =18 so you need 6 gallons to fill it up
By laying on the short edge the frame of it is 6
--Percent means out of 100, so 20% = 20/100
The prob in other words is asking
-- $60 is 20% of what number?
'$60' -- ---> 60
'is' -- ---> =
20% -- ---> 20/100
'of' -- ---> * (multiply)
'what number' ---> x (variable)