Initial mass from the change in period when a known mass is added to a spring

The same question, asked 2 times: 4 May 2023 S2*, 11 May 2024 S2. Every wording below, oldest first.

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Question 1
4 May 2023 S2
40 $A mass 'm' attached to a spring oscillates with a period of 3 second. If the mass is increased by 0.6 kg, the period increases by 3 second. The initial mass 'm' is equal to$
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Question 2
11 May 2024 S2
21 $The upper end of the spring is fixed and a mass 'm' is attached to its lower end. When mass is slightly pulled down and released, it oscillates with time period 3 second. If mass 'm' is increased by 1 kg, the time period becomes 5 second. The value of 'm' is (mass of spring is negligible)$
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Question 1