I need reasons & statements for the problem below.

Calculate the missing value. round the answer to on decimal place. start with 70, increase it by 21%, and end up with

The moats separating people from the animals are 5 m wide for lions and 4 m wide for the elephants. if the lion’s moat is 4 m deep, how deep should the elephants’ moat be?

Solve 4 ln x=2ln25 a) x=5 b) x=25 c) x=625