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 a row of girls,Rita and Monika occupy the ninth place from the right end and tenth place from the left end,respectively. If they interchange their places,Rita and Monika occupy seventeenth place from the right and eighteenth place from the left,respectively. How many girls are there in the row?

How many $18$s are there in the following sequence which are immediately preceded by $9$ but not immediately followed by $7$?
$7, 1, 9, 1, 1, 7, 1, 8, 9, 1, 7, 1, 2, 1, 3, 1, 4, 5, 7, 1, 3, 9, 1, 7$

$A$ 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?

Hemang is $16^{th}$ from the top and $12^{th}$ from the bottom in merit in the class. How many students are there in the class?

In the following sequence of instructions,$1$ stands for Run,$2$ stands for Stop,$3$ stands for Go,$4$ stands for Sit and $5$ stands for Wait. If the sequence were continued,which instruction will come next?
$4, 4, 5, 4, 5, 3, 4, 5, 3, 1, 4, 5, 3, 1, 2, 4, 5, 4, 5, 3, 4, 5, 3$