write a letter to your father requesting him to engage a tutor for you?
My dear father,
I am feeling that I cannot pull only with the class-room studies. I feel weak in (a particular subject). I need extra coaching for that.
So, I request you to allow me to engage a private tutor. One of my school teachers is ready to coach me. He will charge Rs. (something) per month.
Please send your consent and money, so that I may start taking coaching.
Your loving son