If diagonals of a rhombus are 16 cm and 30 cm. then what is the perimeter (in cm) of the rhombus?

The average of nine numbers is 50. The average of first five numbers is 54 and that of the last three numbers is 52, then the sixth number is -

Two numbers are 30% and 37% lesser than a third number. By how much percent is the second number to be enhanced to make it equal to the first number?

Vessels A and B contain mixture of milk and water in the ratios 4 : 5 and 5 : 1 respectively. In what ratio should quantities of mixture be taken from A and B to from a mixture in which milk to water is in the ratio 5 : 4 ? 

129 meter from the foot of a cliff on level of ground, the angle of elevation of the top of cliff is 30 °. The height of this cliff is 

While purchasing one item costing Rs.400, one has to pay sales tax at 7 % and on another costing Rs. 6400, the sales tax was 9%. The percentage of sales tax one has to pay, taking these items together on an average is: 

Direction (66-70): What should come in place of the question mark(?) in the following number series?

12664   34    20  14 ?

9 persons are seated around a round table. What is the probability that two particular persons sit together?