Aloan of 900 will be repaid in 36 installment payments of 30.22 each .what is the finance charge for the loan

If each payment is 30.22 and you have to pay it 36 times,
than you'll pay  (36 x 30.22) = 1,087.92 all together.

But you only borrowed 900 .  Why did you have to pay back 1,087.92 ?
That's (1,087.92 - 900) = 187.92 more than you borrowed.

That amount is called the 'finance charge'. Another name for it is 'interest'.
It's the amount you pay them to keep their money for a while.  In other
words, it's how much extra you pay for not paying the loan back right away.

That's why it's always best to pay the price at the time when you buy something,
and not pay it out over time.  That's why it's not smart to borrow, or use credit cards.