There were red, brown and grey marbles in a bottle. Sean put another 5 red marbles and 4 grey marbles in the bottle, then the ratio of the number of brown marbles to the number of grey marbles became 5 : 3. Then, he doubled the number of red marbles and removed 14 grey marbles. The ratio of the number of red marbles to brown marbles became 2 : 1. He counted and found that there were a total of 148 marbles left in the bottle. Find the number of red marbles that he had at first.

	Red marbles	Brown marbles	Grey marbles	Total
Before	5 u - 5	5 u	3 u - 4
Change 1	+ 5		+ 4
After 1	1x5 = 5 u	5 u	3 u
Change 2	+ 1x5 = 5 u		- 14
After 2	2x5 = 10 u	1x5 = 5 u	3 u - 14	148

The number of brown marbles remains unchanged. Make the number of brown marbles the same. LCM of 1 and 5 is 5.

Total number of marbles in the end
= 10 u + 5 u + 3 u - 14
= 18 u - 14

18 u - 14 = 148
18 u = 148 + 14
18 u = 162

1 u = 162 ÷ 18 = 9

Number of red marbles at first
= 5 u - 5
= 5 x 9 - 5
= 45 - 5
= 40

Answer(s): 40