| Data Sufficiency Butler: April 2025 |
| April 24 | DS 1 | DS 2 |
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DS 1 At a small architecture firm, the average (arithmetic mean) age of the employees at the end of 2025 was 30 years. At the beginning of 2026, one new employee joined the firm and one existing employee left, so the total number of employees remained the same. What was the new average (arithmetic mean) age of the employees after this change?
(1) The employee who left was 2 years older than the new employee who joined.
(2) The employee who left was 30 years old.
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DS 2 At a water-treatment facility, a pump was used to fill an empty storage tank. If the pump operated at a constant rate throughout the process, how many minutes did it take the pump to fill the tank?
(1) If the pump’s flow rate had been 25% greater, the tank would have been filled 16 minutes sooner.
(2) If the pump’s flow rate had been 20% lower, the tank would have taken 20 minutes longer to fill.