Question

At what time between 6:30 and 7 will the hands of a clock be at right angles?

• A. 19
• B. 49
• C. 38
• D. 45 min. past 6
• E. 59 min. past 6

Answer 1

The correct option is B

49

At 6:30, the hands are 2.5 min. spaces apart.

To be at right angles and that too between 6:30 and 7, the minute hand has to gain

(2.5 + 15) = 17.5 min. spaces

$\therefore$ 55 min. spaces are gained in 60 min.

So,17.5 min. spaces are gained in $\left(\frac{60}{55}\times 17.5\right)$min. = $19\frac{1}{11}$min.

$\therefore$ Required time = 49 $\frac{1}{11}$min. past 6.