Here’s the description of the Problem 7:

By listing the first six prime numbers: 2, 3, 5, 7, 11, and 13, we can see that the 6th prime is 13.

What is the 10 001st prime number?

In order to find the solution I wrote a simple function to test whether a number n is prime or not, and then I iterated through all the integers increasing the counter every time a prime is found, until the 10001 was found:

```
#include <stdio.h>
#include <math.h>
int isPrime(num){
int i;
if (num==2)
return 1;
for (i=2;i<sqrt(num)+1;i++){
if (num%i==0)
return 0;
}
return 1;
}
int main(){
int i,counter,ans;
ans=0;
counter=0;
for (i=2;i<200000;i++){
if (isPrime(i)==1){
counter++;
ans=i;
}
if (counter==10001){
break;
}
}
printf("%dn",ans);
return 0;
}
```

rahulsimple algorithm but what was the processing time?