Quantitative Aptitude - Arithmetic Ability Questions

Suppose n is a positive integer such that (n2+ 48) is a perfect square. What is the number of such n?

M is thrice as good as workman as N and together they finish a piece of work in 30 days. In how many days will M alone finish the work?

If A : B = 2 : 5, B : C = 4 : 3 and C : D = 2 : 1, then what is value of A : C : D?

If 27% of an electricity bill is deducted, Rs 1825 is still to be paid. How much was the bill?

The simple interest on a sum for 20 years is 5/4 of the principal. What is the per annum rate (in percentage) of interest?

If m ­ n = 2 , mn = 15 , (m , n > 0) then the value of m2-n2m3-n3

Find the largest number of three digits exactly divisible by 15, 18, 27 and 30.

The mean height of 25 boys in a class is 150 cm, and the mean height of 35 girls in the same class is 145 cm. The combined mean height of 60 students in the class is ___ (app)