How the answer is 4?

Question

String greeting="Sololearn";
System.out.print(greeting.indexOf("Solo"));
System.out.print(greeting.indexOf("Learn"));

Answer 1

when the character is not found in the given string its returns -1.
here 'L' is not there in sololearn so it returns -1.
is output : 0-1

Answer 2

Answer is "04"
Method indexOf(String str) returns the index within this string of the first occurrence of the specified substring.

I think there is a mistake in the task, author meant
String greeting =" SoloLearn"

Answer 3

the answer is not 4, the answer is "0-1"