Quantitative Aptitude - Arithmetic Ability Questions

Mr. Raghav taught Geometry for 36 hours. If the time taken in teaching Ratio consitutes one-fourth of the time for Arithmetic, then for how much time (in hours) did he taught the topic of Ratio?

What is the average of all numbers between 9 and 90 which are divisible by 8?

Two trains are moving in the opposite directions at speed of 43 km/h and 51 km/h respectively. The time taken by the slower train to cross a man sitting in the faster train is 9 seconds. What is the length (in metres) of the slower train?

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

Circum center of ΔABC is O. If ∡BAC = 75 and ∡BCA = 80 degrees,

then what is the value of ∡OAC(in deg)?

x and y are two numbers such that their mean proportion is 16 and third proportion is 128. What is the value of x and y?

A dealer marks his goods 20% above their cost prices. Then,he allows such a discount on the marked price so that he makes a profit of 8%. The rate of discount is:

10% discount is offered on an item. By applying a promo code the customer wins 20% cash back. What is the effective discount?