Unable to get the latest value added to Mysql table based on posted time

SELECT * FROM discussion_comments GROUP BY disc_id ORDER BY posted_date DESC

I have table example like given below:

CREATE TABLE example
(
id int(11),
cname varchar(11),
posted_date date,
posted_time varchar(20)
); 

with values like:

INSERT INTO example
VALUES (1,'abc','2015-03-26','04:25 PM');

INSERT INTO example
VALUES (1,'def','2015-03-27','04:30 PM');

INSERT INTO example
VALUES (2,'ghi','2015-03-11','02:25 AM');

INSERT INTO example
VALUES (2,'jkl','2015-03-15','12:25 PM');

and I am trying to get only the latest value added to the table for an id based on posted_date & posted_time fields.

The result I am trying to achieve is:

(1,'def','2015-03-27','04:30 PM')
(2,'jkl','2015-03-15','12:25 PM') 

The query I tried is as follows:

SELECT * FROM `example GROUP BY id ORDER BY posted_date DESC 

I am not getting the desired result. Where did I go wrong??