Can i have on this question thx : )

Can someone me with this problem i don't understand i need

Apositive number a or the same number a increased by 50% and then decreased by 50% of the result?

When keisha installed a fence along the 200 foot perimeter of her rectangular back yard, she left an opening for a gate.in the diagram below, she used x to represent the length in feet of the gate? what is the value? a. 10 b. 20 c. 25 d. 30