Answer:
As per the question we need to make 5 rowa and 2o columns, in this we have total element 100 so range should be 0 to 99, but we are suggested to keep range 0 to 59, so i have kept the elementns in the range, but if it was a typo in the question for range you do not need to reset the k with zero.
Explanation:
//create a new class  TestArray
public class TestArray {
 //define main method
 public static void main(String[] args) {
  //declare a 2D array of given size i.e. 5 rows and 20 columns
  int arr[][] = new int[5][20];
  //declare an integer variable k and initialize it with zero, this will used to initialize the array from 0 to 99 
  int k = 0;
  //for loop for rows 
  for (int i = 0; i < 5; i++) {
  	//for loop for columns
  	for (int j = 0; j < 20; j++) {
    //initialize arr with the current value of k
    arr[i][j] = k;
    //once k is 59 set it zero again as we are not going beyond 59
    if(k == 59)
    	k = 0;
    //increment value of k with 1
    k++;
  	}
  }
  //print the element from the array one by one
  //for loop for rows 
  for (int i = 0; i < 5; i++) {
  	//for loop for columns
  	for (int j = 0; j < 20; j++) {
    //print the current element of array and an space with it 
    System.out.print(arr[i][j]+" ");
  	}
  	// move the cursor to new line
  	System.out.println();
  }
 }
}