Dear Sir or Madam,
I am writing to you after I saw your advertisement in the magazine. I have interest in applying for the job that you publish.
First, I want to apply for this job because I need extra credit for my trip to Australia. I do like kids so this job is suitable for my interest.
Moreover, I have a sister who has a similar age as your kid. I have the experience to take care of her and help my mother do chores related to taking care of kids. Hence, I have the capability to take look after your kid.
As I told you before, I apply for this job because I need extra credit for my trip to Australia. I will spend my time sightseeing around the city.
I hope that you can give me the opportunity for this job.
Yours faithfully,
Satriyo
Dear Sir or Madam,
I am writing to you after I  
saw
 your advertisement in the magazine. I have interest in applying for the  
job
 that you publish. 
First
, I want to apply for this  
job
  because
 I need extra credit for my trip to Australia. I do like kids  
so
 this  
job
 is suitable for my interest. 
Moreover
, I have a sister who has a similar age as your kid. I have the experience to take care of her and  
help
 my mother do chores related to taking care of kids.  
Hence
, I have the capability to take look after your kid.
As I  
told
 you  
before
, I apply for this  
job
  because
 I need extra credit for my trip to Australia. I will spend my time sightseeing around the city.
I hope that you can give me the opportunity for this job.
Yours  
faithfully
, 
Satriyo