A bag contains 140 balls of various colours. If 30 red balls are added to the bag the proportion of red balls in the bag is doubled. How many red balls were in the bag to begin with?

Respuesta :

Answer:

30

Step-by-step explanation:

because in order for something to double you need it times 2 or add itself together like 30+30 is 60 and that just doubled the original number 30