A large field of 700700 hectares is divided into two parts. The difference of the areas of the two parts is one-fifth of the average of the two areas. What is the area of the smaller part in hectares?  Choose the correct choice from the following.
A) 400 B) 365 C) 385 D) 315 E) 355
Explanation:   Average of the two areas =700/2= 
<gadget id="calculator">700/2</gadget>
<output>350</output>
350   one-fifth of the average of the two areas=350/5= 
<gadget id="calculator">350/5</gadget>
<output>70</output>
70   ⇒ Difference of the two areas=70=70   Let area of the smaller part = x hectares.   Then, area of the larger part =x+70 hectares.   x+(x+70)=700   ⇒2x=630   ⇒x=315   Answer: Option 315
<result>D</result>
A large field of 700700 hectares is divided into two parts. The difference of the areas of the two parts is one-fifth of the average of the two areas. What is the area of the smaller part in hectares?