Please Help! I will give you a lot of points! (It's really the guess & check I'm having trouble with. Is there an easier way to find the standard divisor (d)?)

Four people pool their money to buy 60 shares of stock. The amount that each person contributes is shown in the following table. Use Adam's method with d=108 to apportion the shares of stock.

----Only pay attention to number 12 in the picture