6. TBQ - Find the time taken

A water tank is filled from a tap. If the tap is open for \(1\) hour, \(\frac{7}{10}\) of the tank gets filled. How much of the tank is filled if the tap is open for 

 

(a) \(\frac{4}{5}\) hour \(=\)  $\frac{i}{i}$of the tank is filled 

 

 

Ans: $i\frac{i}{i}$ \(\text{hours}\)

 

[NOTE: Write answer in simplified form.]