Initially, the ratio of ed’s toy cars to pete’s toy cars was 5: 2. after ed gave 30 toy cars to pete, they each had an equal number of toy cars. how many toy cars did they have altogether?

So here is the answer. Initially, Ed's toy cars compared to Pete's toy cars was 5:2. So for every 5 cars that Ed has, Pete has 2. Now that Ed gave 30 cars to Pete. So here it goes. The total number of ratio units is 5+2=7, so each will have an equal number if they both have 3.5 ratio units. That is, if Ed transfers to Pete 1.5 ratio units, their car counts will be equal. Thus 1.5 ratio units = 30 cars, or 1 ratio unit = 20 cars. Therefore, this makes  7*20 cars = 140 cars.
Hope this helps.