One parking lot had three times fewer cars than the other. After 18 cars arrived

One parking lot had three times fewer cars than the other. After 18 cars arrived at the first parking lot and 10 cars left the second, it became equal in both parking lots. How many cars were in each parking lot initially?

Let us denote by the variable x the number of cars that were in the first parking lot.

Then the number of cars that were in the second parking lot can be expressed in terms of 3x.

Knowing that after 18 cars arrived at the first and 10 left the second, it became equal in both parking lots, we will draw up an equation and determine the initial number of cars in each parking lot:

x + 18 = 3x – 10;

2x = 28;

x = 14;

3 * 14 = 42.

Answer: Initially, there were 14 cars in the first parking lot, and 42 in the second.