The amount he need to borrow is:
$ 18
It is given that:
The amount Sonny has in order to spend= $ 75
Also, the amount that is required to make a purchase= $ 93
Now, he has less money to purchase, so he need to borrow extra money.
The amount that he need to borrow is:
Amount required to make a purchase-Amount Sonny has
i.e.
Amount he need to borrow=$ (93-75)
i.e.
Amount he need to borrow=$ 18
