The difference between a number and its two-fifth is 510. What is 10% of that number?  Pick one.
A) 58
B) 85
C) 76
D) 68
E) 86
Let the number be x. Then,   x - 2/5 x = 510   x = (510 * 5)/3= 
<gadget id="calculator">(510 * 5)/3</gadget>
<output>850</output>
850   10% of 850= 85.   Answer:85
<result>B</result>
The difference between a number and its two-fifth is 510. What is 10% of that number?