Quantitative Aptitude - Arithmetic Ability Questions

The average height of 30 boys out of a class of 50 is 160 cm. If the average height of the remaining boys is 165 cm, the average height of the whole class (in cm) is:

The line passing through point (-3,1) and point (x,5) is parallel to the line passing through point (-2,-1) and point (6,3). What is the value of x?

The ratio of present ages of Ramya and Saurabh is 8:7. After 10 years the ratio of their ages will be 12:11. What is Ramya's present age?

Pankaj has done 1/2 of a job in 12 days, Sainath completes the rest of the job in 6 days. In how many days can they together do the job?

Selling price of a calculator is Rs 13924 and profit percentage is 18%. If selling price is Rs 10266, then what will be the loss percentage?

What is the value of sin 5π/3?

If cosπ/4c - tanπ/4c = x, then x is

Speeds of a boat along the current and against the current are 14 km/hr and 7 km/hr respectively. What is the speed of boat (in km/hr) in still water?