Is anything wrong in this code

Question

puts"What is your age?"
a = gets.to_i
case a
when a<19
puts "You are a teenager."
when a>19 && a<40
puts "You are a adult."
when a>40
puts "You are too old."
end

Answer 1

instead of when use if with a semicolon at end of statement

Answer 2

if you are python user then use this
age=input ("Enter your age:")
if a<19:
print "you are teenager"
if a(20,40):
print "you are an adult"
if a>40:
print "you are too old"

Answer 3

As I see it, if you're 19 or 40 you're nothing