Answer:
Step-by-step explanation:
write a proportion and cross multiply to solve for x
[tex]\frac{60}{100} = \frac{x}{1280}[/tex]
100x=76,800
x=768
60% full is 768 L. If the tank can hold 1,280 Liters, you need 512 more to fill it.
Alternatively...if the tank is 60% full, we need 40% more to fill it
[tex]\frac{40}{100} =\frac{x}{1280}[/tex]
100x=51,200
x=512 L
