Answer:
As i understand it:
The total park is 2.4 ha
10% of that is paths and 15% of that is a lake.
So a 10% + 15% = 25% is taken.
So we have left a 75% of the park, this is:
Left = (75%/100%)2.4 ha = 0.75*2.4ha = 1.8 ha.
Now we also need to subtract the are of the tennis court.
The tennis court occupies a rectangular plot of 60m by 50m (you actually wrote cm here, but i guess it was a mistake, we can not have a tennis court of 60cm by 50cm)
So the area of the tennis court is:
A = 60m*50m = 3,000 m^2
But we want to write it in ha
We know that:
1ha = 10,000m^2
then 3,000m^2 = (3,000/10,000) ha = 0.3 ha
Then the left area is:
L = 1.8 ha - 0.3ha = 1.5 ha.