Quantitative Aptitude - Arithmetic Ability Questions

Given there are 9 flavours of ice creams.

Each child takes the combination of two flavours and no two children will have the same combination

This can be done by  ways i.e children.

Number of children=C29  = 9 x 8 / 1x 2 = 36.

 Clearly, to find the average, we ought to know the number of boys, girls or students in the class, neither of which has been given.

So, the data provided is inadequate.

v1v2=r12Hr22H

Let the age of A = A, B = B and C = C

From given

A = 3B

4 years ago,

C-4 = 2(A-4);

After 4 years

A + 4 = 31;

A = 27;
sub in above B, we get B = 9
C = 2(27 - 4) + 4 = 46 + 4 = 50

Hence B = 9yrs and C = 50yrs.

Let the numbers be x and y. Then,

x^2+y^2=3341......(1)

x^2-y^2=891......(2)

Adding (i) and (ii), we get : 2x^2=4232 or x^2= 2116 or x =46

Subtracting (ii) from (i), we get : 2y^2= 2450 or y^2 = 1225 or y = 35

So, the numbers are 35 and 46

The day of the week repeats every 7 days.

Given today is Friday. Again Friday is repeated on the 7th day, 14th,... on 7 multiple days.

Hence, Friday is on the 63rd day, as 63 is multiple of 7.

Now, the required day of the week on the 65th day is Sunday.

Let their edges be a and b. Then,

a3/b3 = 1/27 (or) (a/b)3 = (1/3)3 (or) (a/b) = (1/3).

\Ratio of their surface area = 6a2/6b2 = a2/b2 = (a/b)2 = 1/9, i.e. 1:9.