A ray of light falls on a plane mirror with an angle of incidence equal to 60°. The angle of reflection is
How many factors are there for the resulting number 1 x 7 x 37 x 41?
A number when divided by 14 leaves a remainder 9. If the same number is divided by 7, what can be the remainder?
6 is the first perfect number. What is the next perfect number?
Read the following instructions and answer the questions given below
A and B are friends and their age differ by 2 years. A’s father D is twice as old as A and B is twice as old as his sister C. The age of D and C differ by 40 years.
How old is A?
How old is B?
How much older is A than B ?
Distance from a place A to another place B is 200 km. A car takes 3½ hours to go from A to B and 4½ hours to return from B to A. What is the average speed of the car in the whole journey?
What should be added to 5820 so that it is divisible by 18 ?
Which is the only number other than 0 to 1 whose square root is equal to the sum of the digits ?
Fill in the missing number in the series
3, 6, 18, 9, 18, 54, 27, 54, 162
One person sees his image in a mirror. If he walks backwards with a speed of 5 m./hour he sees his image moving with a speed of
How many of the numbers between 200 and 500 begin or end with 3 ?
The ratio between the ages of father and son is 5 : 2. If seven years ago the father was 43 years old, what is the present age of son?
The radius of a sphere is increased by 50%. The percentage increase in surface area is