Let the capacity of the tank be x litres
(1/6)x + 21 = (3/4)x
solve for x to find the capacity of the tank.
I am sure you can take it from there, e.g.
1/6 of the tank is ...
then 21 litres were added, how many more are
needed to fill it ?
A gasoline tank is 1/6 full. When 21 liters of gasoline were added, it became 3/4 full. How many more liters more is needed to fill it?
3 answers
V = Volume of tank
A gasoline tank is 1/6 full. When 21 liters of gasoline were added, it became 3/4 full mean:
( 1 / 6 ) V + 21 = ( 3 / 4 ) V
( 1 / 6 ) V + 21 = ( 3 / 4 ) V
Subtract ( 1 / 6 ) V to both sides
21 = ( 3 / 4 ) V - ( 1 / 6 ) V
___________
Remark:
3 / 4 = 9 / 12
1 / 6 = 2 / 12
__________
21 = ( 9 / 12 ) V - ( 2 / 12 ) V
21 = ( 7 / 12 ) V
Multipy both sides by 12
21 * 12 = 7 V
252 = 7 V
Divide both sides by 7
252 / 7 = V
36 = V
V = 36 liters
36 liters - 21 liters = 15 liters
A gasoline tank is 1/6 full. When 21 liters of gasoline were added, it became 3/4 full mean:
( 1 / 6 ) V + 21 = ( 3 / 4 ) V
( 1 / 6 ) V + 21 = ( 3 / 4 ) V
Subtract ( 1 / 6 ) V to both sides
21 = ( 3 / 4 ) V - ( 1 / 6 ) V
___________
Remark:
3 / 4 = 9 / 12
1 / 6 = 2 / 12
__________
21 = ( 9 / 12 ) V - ( 2 / 12 ) V
21 = ( 7 / 12 ) V
Multipy both sides by 12
21 * 12 = 7 V
252 = 7 V
Divide both sides by 7
252 / 7 = V
36 = V
V = 36 liters
36 liters - 21 liters = 15 liters
The question was , "How many more litres are needed to fill it?
the tank holds 36 litres, we both have that
it already holds (1/6)(36) or 6 L
21 more are added, so now we have 27 L, which is 3/4 of the tank,
so 9 more litres are needed to fill it.
the tank holds 36 litres, we both have that
it already holds (1/6)(36) or 6 L
21 more are added, so now we have 27 L, which is 3/4 of the tank,
so 9 more litres are needed to fill it.
1 answer