16L more? it became 80% when another 40 L is added. that means 50%-40L
you'll get 1% when 40 divide by 50, and multiply with 20 because the question asked the amount of oil needed to fill up the tank. i hope that it would help.
Jawapan Paling Bijak!
16,because 80%-30%=50%  50%=40litres
                                                      5%=4 litres
100%-80%=20%      20% is the amount needed to fill up the tank.
5% X 4=20%  4litres X 4=16litres          So the answer is 16 litres
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