You decided to give your friend marbles for his birthday. Since you know he like red marbles better than brown ones, the number of red marbles in the bag is 4 fewer than 5 times the number of brown marbles. The bag contains 74 marbles. Which system of equations can be used to determine r, the number of red marbles and b, the number of brown marbles?
r + 5b = 4 r + b = 74
r + 5b = 74 r - b = 4
4 - 5b = r 5b + r = 74
5b - 4 = r r + b = 74