Timothy had a total of 238 blue and red marbles. He gave 3/7 of the blue marbles and 5/8 of the red marbles away. Altogether, Timothy gave away 124 marbles.How many red marbles did Timothy give away? (Skill: Equations)

Answer 1

B + R = 238
3B/7 + 5R/8 = 124
Multiply both sides of the last equation by 8/5.
24B/35 + R = 198.4
Subtract the above equation from the first one.
11B/35 = 39.6
Multiply both sides by 35/11
B = 126
R = 112 is the number of red marbles.

Answer 2

654
87
567