A driving school uses this rule to estimate how many lessons a learner will require.
- Every learner requires at least 20 lessons
- learners over the age of 18 require more lessons (two additional lessons for each year over 18)
Create an algorithm expressed in pseudo-code that inputs a learner's age and calculates the number of driving lessons they will need.

So far, this is what I've come up with:
RECEIVE age FROM KEYBOARD
SET lessons TO 20 + (2 * (age – 18))
IF age >= 18 THEN
SEND lessons TO DISPLAY
ELSE
SEND ‘You’re not old enough. Come back later.’ TO DISPLAY
END IF

but I'm not sure if I've done it correctly or used the operators correctly.