Quantitative Aptitude - Arithmetic Ability Questions

If a + b = 10 and ab = 21, then the value of (a - b)2 is

The value of ds+t÷ds÷dt

Product of 6ab, 3b and 4a 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?

19 personswentto a hotel for a combineddinner party. 13 of them spent Rs 79 each on their dinner and the rest spent Rs 4 more than the average expenditure of all the 19. What was the total money spent by them?

In a class of 56 students there are 28 girls. The average weight of these girls is 46 kg and average weight of the full class is 51 kgs. What is the average weight of the boys of the class?

In each of the following questions, a question is followed by information given in them Statements I, II and III. You have to study the question along with the statements and decide the information given in which or the statements/ is necessary to answer the question. 

What is the cost of flooring the rectangular hall?

I. Length and the breadth of the hall are in the ratio of 3:2

II. Length of the hall is 48 m and cost of flooring is ₹ 850 Per sq.m.

III. Perimeter of the hall is 160 m and cost of flooring is ₹ 850 per sq m

If cost price of 5 cars is equal to selling price of 4 cars. Find the percentage of profit or loss?