Ajay left home for the bus stop $15 \,minutes$ earlier than usual. It takes $10 \,minutes$ to reach the stop. He reached the stop at $8:40 \,a.m.$ What time does he usually leave home for the bus stop?

In the series,$6, 4, 1, 2, 2, 8, 7, 4, 2, 1, 5, 3, 8, 6, 2, 1, 7, 1, 4, 1, 3, 2, 8, 6$,how many pairs of successive numbers have a difference of $2$ each?

Abhishek ranks thirteenth in a class of thirty-one students. What is his rank from the last (in $19^{th}$)?

Saiyeev ranks seventh from the top and twenty-eighth from the bottom in a class. How many students are there in the class?

In a row of $21$ girls, when Anita was shifted by four places towards the right, she became $12^{th}$ from the left end. What was her earlier position from the right end of the row (in $^{th}$)?

$A$ monkey climbs $30$ feet at the beginning of each hour and rests for a while,during which he slips back $20$ feet before he again starts climbing at the beginning of the next hour. If he begins his ascent at $8:00 \, a.m.$,at what time will he first touch a flag at $120$ feet from the ground?