In an examination in which the full marks were 500, A scored 25% more marks than B, B scored 60% more marks than C and C scored 20% less marks than D. If A scored 80% marks, then the percentage of marks obtained by D is:

Given, Total marks = 500

A scored 80% marks in the examination

$$\Rightarrow$$  A = $$\frac{80}{100}\times500$$ = 400

A scored 25% more marks than B

$$\Rightarrow$$  A = $$\frac{125}{100}$$B

$$\Rightarrow$$  400 = $$\frac{125}{100}$$B

$$\Rightarrow$$  400 = $$\frac{5}{4}$$B

$$\Rightarrow$$  B = 320

B scored 60% more marks than C

$$\Rightarrow$$  B = $$\frac{160}{100}$$C

$$\Rightarrow$$  320 = $$\frac{160}{100}$$C

$$\Rightarrow$$  C = 200

C scored 20% less marks than D

$$\Rightarrow$$  C = $$\frac{80}{100}$$D

$$\Rightarrow$$  200 = $$\frac{80}{100}$$D

$$\Rightarrow$$  D = 250

$$\therefore\ $$Percentage of marks obtained by D = $$\frac{250}{500}$$ = 50%

Hence, the correct answer is Option C