Ben and Jerry had 530 cards. Both of them lost some cards in a game. Ben lost of his cards and Jerry lost of his cards. Then, Ben and Jerry had 370 cards left. How many cards did Ben have at first?

PROBLEM 21: A casino game involves shuffling a standard deck of 52 playing cards, and then randomly selecting one of the cards from the shuffled deck. If the selected card is an Ace, the player wins $1, and if not, the player wins nothing. If 104,000 people play the game once each during a given day at the casino, how many of them should we expect to win the game? A) 800 B) 16,000 C) 8,000 D) 2,000 E) none of the above

Jason had 40% fewer coins than Tom. Jason gave his sister some of his coins. As a result, the number of coins he had decreased by 25%. How many coins did Jason have left in the end if both of them had 58 coins altogether in the end?

Mathematics fractions:

Darius, Ellen and Farhan each had some marbles. They traded marbles with one another. In the 1st round, Darius gave 1/5 of his marbles to Ellen.

In the 2nd round, Ellen gave 1/4 of his marbles to Farhan.

In the 3rd round, Farhan gave 1/2 of his marbles to Darius.

Darius had 45 marbles, Ellen had 30 marbles, and Farhan had 25 marbles left in the end.

How many marbles had each of them at first?