Answer:
weeks
Step-by-step explanation:
Given
It takes 14 weeks to empty a lake
also it takes 20 weeks for a river to fill the lake
Part of lake empty in 1 week 
Part of lake filled in 1 week is 
And if both works simultaneously then


therefore it takes
weeks to fill it
Answer:
A = 12.92
Step-by-step explanation:
Base x Height x 1/2
3.4 x 7.6 = 25.84
26.52 x 1/2 = 12.92
Hope this helps :)