Question

What is the reflex angle between the hands of a clock at 8:30?

A 197⁰ Correct Answer Incorrect Answer
B 285⁰ Correct Answer Incorrect Answer
C 185⁰ Correct Answer Incorrect Answer
D 255⁰ Correct Answer Incorrect Answer

Solution

Angle traced by hour hand 17/2 hours = (360/12× 17/2)^⁰ = 255⁰ Angle traced by minute hand in 30 minutes = (360/60× 30)^⁰ = 180⁰ ∴ Reflex angle = 360⁰ - (255⁰ - 180⁰) = 360⁰ - 75⁰ = 285⁰ Alternate shortcut method: The angle between the two hands of a clock of 30 minutes past 8 O’clock θ=11/2 m-30h =11/2×30-30×8 = 165-240= 75° (Here, -ve sign does not matter) So reflex angle = 360 – 75 = 285°

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