After giving 1/3 of his football cards to his brother and 2/5 of the remainder to his sister, max had 30 left. how many cards did he have to begin with? ( show steps! )

1) if 30 is 2/5 of x, than 15 is 1/5 of x. 1/5 times 5 equals one. 15 times 5 equals 75. 
2) if 75 = 1/3 of x, than just do 75 times 3 to get x, which is 225. 

So he has 30 that means he gave 20 to his sister (2/5 of 50= 20)

before he had given them to his sister, he had 50, and that was after he gave 1/3 of his cards to his brother, that means he gave 25 cards to his brother. and max had 75 cards to begin with

(deeper explaination(ish))
75/3=25 (25=1/3 of his original amount)
he then had 50 left and gave 2/5 of them to his sister(50/5=10 and two of those =20. he is then left with 30 cards)

if any of this confuses you tell me and I will do my best to correct it xD

The answer is a. point