Quantitative Aptitude - Arithmetic Ability Questions

A boat covers 143 km upstream in 13 hours and the same distance downstream in 11 hours. What is the speed (in km/hr) of the boat in still water?

If 40 is 0.05% of x, then what is the value of x?

The length of one side of a rhombus is 13 cm and one of the diagonals is 10 cm. What is the legth of the other diagonal?

If a = 3+23-2, b = 3-23+2 then a2+b2-ab ?

If x1x2x3 = 4(4 + x1 + x2 + x3 ), then what is the value of [1/(2 + x1 )] + [1/(2 + x2 )] + [1/(2 + x3 )]?

The sum of all prime numbers between 18 and 32 is:

Convert decimal number 101 to binary.

A, B and C can do a job working alone in 6, 9 and 18 days respectively. They all work together for 1 day, then A and B quit. How many days C working alone will take to complete the remainder of the job?