A clock strikes once when its hour hand is at one, twice when it is at two and so on. How many times does the clock strike in twelve hour?

378 trees are planted in rows in the shape of an isosceles triangle, the numbers in successive rows decreasing by one from the base to the top. How many trees are there in the row which forms the base of the triangle?

The prize money Rs60,000 will be distributed among the eight teams according to their positions determined in the match-series. The award increases by the same amount for each higher position. If the last place tem is given Rs.4000 , how much will be awarded to the first place team?

An investor earned Rs. 6000 for year 1980 and Rs. 12000 for year 1990 on the same investment. If his earning have increased by the same amount each year, how much income he has received from the investment over the past eleven years?

A student saves Rs. 12 at the end to the first week and goes on increasing his saving Rs. 4 weekly. After how many weeks will be able to save Rs. 2100?

An equilateral triangular base is filled by placing eight balls in the first row, 7 balls in the second row and so on with one ball in the last row, After this base layer, second layer is formed by placing 7 balls in the first row, 6 balls in the second row and so on with one ball in its last row. Continuing this process, a pyramid of balls is formed with one ball on top. How many balls are there in the pyramid?

The sum of interior angles of polygons having sides 3,4,5,... . etc from an A.P. Find the sum of the interior angles for a 16 sided polygon.

A man borrows Rs.1100 and agree to repay with a total interest of Rs.230 in 14 installments, each installment being less than the preceding by Rs. 10 . What should be his first installment?

An object falling from rest, falls 9 meters during the first second, 27 meters during the next second, 45 meters during the third second and so on. How far will it fall during the fifth second?

An object falling from rest, falls 9 meters during the first second, 27 meters during the next second, 45 meters during the third second and so on. How far will it fall up to the fifth second?