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At what time between 7 and 8 o'clock will the hands of a clock be in the same straight line but, not together?

Option :

Explanation:

Solution:
When the hands of the clock are in the same straight line but not together, they are 30 minute spaces apart.
At 7 o'clock, they are 25 min. spaces apart.
∴ Minute hand will have to gain only 5 min. spaces.
55 min. spaces are gained in 60 min.
5 min. spaces are gained in
$\begin{array}{rl}& \left(\frac{60}{55}×5\right)\phantom{\rule{thinmathspace}{0ex}}min=5\frac{5}{11}\phantom{\rule{thinmathspace}{0ex}}min\\ & \therefore \text{Required}\phantom{\rule{thinmathspace}{0ex}}\text{time}=5\frac{5}{11}\phantom{\rule{thinmathspace}{0ex}}min.\phantom{\rule{thinmathspace}{0ex}}past\phantom{\rule{thinmathspace}{0ex}}7\end{array}$