RRB Technician Grade III · 29 Dec 2024 · Shift 1 — Mathematics
RRB Technician · previous year paper
1 Mathematics questions from RRB Technician Grade III · 29 Dec 2024 · Shift 1, with answers and Hindi and English explanations.
1.
एक पाइप एक टंकी को 12 घंटे में भर सकता है। दूसरा पाइप भरी हुई टंकी को 28 घंटे में खाली कर सकता है। यदि दोनों पाइपों को एक साथ खोल दिया जाए, तो टंकी का एक-तिहाई भाग भरने में कितना समय (घंटे में) लगेगा?
A pipe can fill a tank in 12 hours. Another pipe can empty the filled tank in 28 hours. If both the pipes are opened simultaneously, then the time (in hours) in which the tank will be one-third filled, is:
- (A)14
- (B)21
- (C)28
- (D)7
Show answer and explanation
Answer: (D)
7
प्रति घंटे शुद्ध भराव = 1/12 − 1/28 = 7/84 − 3/84 = 4/84 = टंकी का 1/21। टंकी का 1/3 भाग भरने में लगा समय = (1/3) ÷ (1/21) = 7 घंटे। अतः उत्तर 7 है।
Net filling per hour = 1/12 − 1/28 = 7/84 − 3/84 = 4/84 = 1/21 of the tank. Time to fill 1/3 of the tank = (1/3) ÷ (1/21) = 7 hours. So the answer is 7.
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