Answer:

Explanation:
Mr. Kim, his wife and two children are 4 persons. Now, he needs to buy 3 plane tickets for each one, which means he has to buy 12 plane tickets:

On the other hand, we know each ticket costs
per person. So, if we have 12 tickets to buy, we will have to multiply
by 12:
This is the amount Mr. Kim will spend in the plane tickets