Quantitative Aptitude - Arithmetic Ability Questions

The average marks of 45 students is shown as 65. It includes a wrong entry of 84 marks instead of 48 marks. The correct average is:

An alloy is made by mixing metal A costing Rs 2000/kg and metal B costing Rs 400/kg in the ratio A:B = 3:1. What is the cost (in Rs) of 8 kilograms of this alloy?

Ramesh and Rahman can do a work in 20 and 25 days respectively. After doing collectively 10 days of work, they leave the work due to illness and Suresh completes rest of the work in 3 days. How many days Suresh alone can take to complete the whole work ?

Seven years ago, the age of Sahil was equal to the present age of Nihal. Sum of Sahil's age 5 year ago and Nihal's age 6 years later is 58 years. If Ruchi is 4 years elder to Sahil, then what will be Ruchi's age (in years) after 10 years?

Find length of the arc whose central angle is 45° and radius of the circle is 28 cm?

Product of 6ab, 3b and 4a is

In ∆DEF measure of angle E is 90°. If secD = 25/7, and DE = 1.4cm, then what is the length (in cm) of side DF?

If the amount received at the end of 2nd and 3rd year at compound interest on a certain Principal is Rs 30250, and Rs 33275 respectively, what is the rate of interest?