John has a collections of 20 minute cars and trucks. cars make up 40% of the collection. of john adds cars to the collections how many cars must he add to make up 75% of cars

Given that John has a collections of 20 cars and trucks and cars make up 40% of the collection.

Thus, the number of cars in the collection is given by



If john adds cars to the collections, the number of cars he must add to make up 75% of cars is obtained as follows:

Let x be the number of cars he must add, then



Therefore, the number of cars he must add to make up 75% of cars is 28 cars.