A man has to exert a force of 10 N at the edge of a door to push it open. How much,force will the man have to exert if he pushes the centre of the door?

The first battery was made by

The average height of 12 students in a class was calculated as 152 cm. On verification it was found that one reading was wrongly recorded as 148 cm instead of 172 cm. Find the correct mean height

The difference of the squares of two positive numbers is 45. The square of the smaller number is four times the larger number. Find the numbers

The radius of a cart wheel is 35 cm. How many revolution does it make in travelling a distance of 154 m

Saran is 6 times as old as his son Sankar. After 4 years, he will be 4 times as old as
his son. What are their present ages?

Express 0.35(bar) into fraction

How many numbers are there between 200 and 300 which are exactly divisible by 6,8 and 9?

A can do a piece of work in 20 days and B can do it in 30 days. How long will they take to do the work together?

If 14 compositors can compose 70 pages of a book in 5 hours, how many compositors will compose 100 pages of this book in 10 hours?