The minute hand of a clock overtakes the hour hand at intervals of 70 min of the correct time. How much in a day does the clock gain or loss?

Given that, time to overtake N = 70 min
The required result = [(720/11) - N) ] x [(60 x 24)/N) min
= [(720/11) - 70) ] x [(60 x 24)/70) min
= [(720 - 770) / 11] x [(60 x 24) / 70] min
= - (50/11) x [(6 x 24)] / 7 min = -7200/77 min
-ve sign indicates that there is a loss.