21.

The distance between 2 places R and S is 42 km. Anita starts from R with a uniform speed of 4 km/h towards S and at the same time Romita starts from S towards R also with some uniform speed. They meet each other after 6 hours. The speed of Romita is

• 18 km/hr

• 3 km/hr

• 20 km/hr

• 20 km/hr

If the side of a square is  and its diagonal is  then the length of the side of the square would be

• 
• 

• 1 unit

• 1 unit

If 2s = a + b + c, then the value of s(s - c) + (s - a) (s - b) is

• ab

• abc

• 0

• 0

If p + m = 6 and p³ + m³ = 72, then the value of pm is

• 6

• 12

• 9

• 9

When x^m is multiplied by xⁿ ,product is 1. The relation between m and n is

• mn = 1

• m = n

• m + n = 1

• m + n = 1

The area (in square units) of the triangle formed by the graphs of the equations x = 4,  y = 3 and 3x + 4y = 12 is

• 24

• 12

• 6

• 6

If  then the value of  is

• 7

• 

• 1

• 1

If the ordinate and abscissa of the point (k,  2k -1) be equal, then the value of k is

• 0

• -1

• 1

• 1

ABC is a triangle in which DE || BC and AD : DB = 5 : 4. Then DE : BC is

• 4 : 5

• 4 : 9

• 9 : 5

• 9 : 5

The radii of two concentric circles are 17cm and 25 cm. A straight line PQRS intersects the larger circle at the points P and S and intersects the smaller circle at the points Q and R. If QR = 16cm, then the length (in cm.) of PS is

• 41

• 32

• 33

• 33