Su Mei bought 3 apples for $2n. How much did she have to pay for 18 apples?
Cross multiply and solve for x.
3/2 = 18/x
To find out how much Su Mei had to pay for 18 apples, it is necessary to determine the price of one apple first.
Given that Su Mei bought 3 apples for $2n, we can calculate the price of one apple by dividing the total cost by the number of apples.
So, the cost of one apple is ($2n) / 3.
To find out how much Su Mei had to pay for 18 apples, we can multiply the cost of one apple by the number of apples.
Therefore, Su Mei had to pay (18 * ($2n) / 3) for 18 apples.