The difference between a number and two-fifths of it is 510. What is 10% of that number?
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → 85
Taking two-fifths away from a number leaves three-fifths of it.
\(\displaystyle x-\frac{2}{5}x=\frac{3}{5}x=510\)
\(\displaystyle x=\frac{510\times5}{3}=850\)
10% of 850 \(=85\)
10% of the number is 85.