That's simple. Veryyyyyyyyyyyyy easy!! Who on Earth doesn't know?
Anyway,
We will share $12,000,000 in the ratio 6:5:4
Husband : Son : Wife : Sum
6 : 5 : 4 : 15
? : ? : ? : $12,000,000
So,
Husband takes: 12,000,000*6/15 = $4,800,000
Son takes: 12,000,000*5/15 = $4,000,000
Wife takes: 12,000,000*4/15 = $3,200,000
Another way:
12,000,000/15 = 800,000
So,
Husband takes: 800,000*6 = $4,800,000
Son takes: 800,000*5 = $4,000,000
Wife takes: 800,000*4 = $3,200,000
Clarification: You dude will divide the original number which is 12 M by 15, you will get 800,000 right? which is only 1 part of the ratio. If the husband takes 6 parts then multiply 800,000 by 6 and you will get the answer. The same with the son and wife. Got it, dear guest?
After all, was that your homework?