Q:

Can't find the symbol on line 10?

 //Question
            String readyOne = console.readLine("Are you ready for your first question?  ");
            console.printf(readyOne);
            if (readyOne.equalsIgnoreCase("yes")) {
            String questionOne = console.readLine("1 + 1 =  ");
            console.printf(questionOne); }

          //Answer
          if (questionOne.equals("2") || 
              questionOne.equalsIgnoreCase("two")) {
              console.printf("Well done");
          }

error:
symbol:   variable questionOne
location: class oldjack
oldjack.java:36: error: cannot find symbol 
          questionOne.equalsIgnoreCase("two")) {
          ^
symbol:   variable questionOne
location: class oldjack
2 errors

A:

This is a typical example why code formation matters:
String readyOne = console.readLine("Are you ready for your first question?  ");
console.printf(readyOne);
if (readyOne.equalsIgnoreCase("yes")) {
    String questionOne = console.readLine("1 + 1 =  ");
    console.printf(questionOne);
} // lifeness of questionOne ends here

// Answer
if (questionOne.equals("2") || questionOne.equalsIgnoreCase("two")) {
    console.printf("Well done");
}

The variable questionOne is only alive and visible within the first if-block
To fix this problem, one can move the 2nd if into the first if:
String readyOne = console.readLine("Are you ready for your first question?  ");
console.printf(readyOne);
if (readyOne.equalsIgnoreCase("yes")) {
    String questionOne = console.readLine("1 + 1 =  ");
    console.printf(questionOne);
    // Answer
    if (questionOne.equals("2") || questionOne.equalsIgnoreCase("two")) {
        console.printf("Well done");
    }
}

