Question

Four machine makes a beep after every 15, 30, 40 and 45 minute respectively. In 30hrs, how many times do they beep together if they have just beeped together?

A 5 times Correct Answer Incorrect Answer
B 15 times Correct Answer Incorrect Answer
C 10 times Correct Answer Incorrect Answer
D 8 times Correct Answer Incorrect Answer
E None of these Correct Answer Incorrect Answer

Solution

LCM of 15, 30, 40 and45 = 360 That me ans: after 360 minute they will beep again together. 1360 minute = `360/60` hrs = 6hrs Then number of beep in 30hrs = `30/6` = 5 times

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