The **digital root** of a number is obtained by adding together the digits of that number, and repeating that process until a number is arrived at that is less than \(10\).

For example,for \(29953\) the **digital root** is \(29953 \rightarrow 28\rightarrow 10\rightarrow 1\).

Consider the set \(P\) of all prime numbers less than **two million**.If \(x\) is the **percentage** of numbers in \(P\) with a **digital root** of 2,what is the value of \(\left\lfloor 1000x \right\rfloor\) ?

**Details and assumptions**

\(\left\lfloor x \right\rfloor \) is the floor function and it returns the greatest integer less or equal to \(x\). ie \(\left\lfloor 1.234 \right\rfloor =1\)

×

Problem Loading...

Note Loading...

Set Loading...