The total cost for 1 adult ticket and 3 child's tickets if the adult fare is 540.00 and the child fare is two thirds of the adult fare

1/3 * 540 is your answer

First to figure out how much a child's ticket is, find two thirds of 540. The easiest way to do this is to find one third of it and multiply that by two
540/3 = 180
180 x 2 = 360
360 is how much a child's ticket costs. The question is asking for 3 children and one adult
540 + (360x3)
1620 is the total