a ticket for an adult visiting an exhibition cost X. a ticket for a child cost $30 less than an adults ticket. write down, in terms of x, the cost of a child's ticket.

how about

x-30

?

To find the cost of a child's ticket in terms of X, we need to consider that a child's ticket costs $30 less than an adult's ticket.

Let's denote the cost of an adult ticket as X.

The cost of a child's ticket can be derived by subtracting $30 from the cost of an adult ticket, which gives us:

X - $30

Therefore, the cost of a child's ticket, in terms of X, is X - $30.