Lian buys a number of notebooks for ¥84. If he had bought 2 more notebooks for the same amount, each notebook would have cost ¥1 less. How many notebooks did he buy?
A lamp is 29.7m above the ground. A boy 77cm tall walks away from the base of this post at a speed of 1.8m/s. Find the length of the shadow of the boy after 9seconds.
A building is in form of a right circular cylinder and cone as shown in the picture. The radius of cone and cylinder is 4 meters. The height of cylinder and cone are 8 meters and 3 meters respectively. Find the outer surface area of the building. (Assume π =
In this diagram, the triangle represents men, the square represents inspectors and the circle represents employed. Find the number of men who are inspectors and employed.