Question
There were some marbles in Packet C and Packet D. After Andy transferred 15 of the marbles from Packet C to Packet D, the ratio of the number of marbles in Packet C to that in Packet D changed to 3 : 5. Find the ratio of the numbers of marbles in Packet C to the number of marbles in Packet D at first.
3 m

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There were some marbles in Packet C and Packet D. After Andy transferred 15 of the marbles from Packet C to Packet D, the ratio of the number of marbles in Packet C to that in Packet D changed to 3 : 5. Find the ratio of the numbers of marbles in Packet C to the number of marbles in Packet D at first.