Arithmetical Reasoning Questions

The nine pieces consist of 8 smaller equal pieces and one half cake piece.
Weight of each small piece = 15 g.
So, total weight of the cake = [2 x (15 x 8)]g = 240 g.

As clear from the figure itself, triangle OQX and triangle O'PX are similar.

So,

OQ/O'P = OX/O'X

=> OX = (7/9)xO'X

And since, OX + O'X = 20

=> (7/9)xO'X + O'X = 20

=> O'X = 45/4

If 'k' is number of students in P and 'l' is number of students in Q, then
From the given conditions, we have
=> k - 10 = l + 10 .......(1)
=> k + 20 = 2(l - 20) ....(2)

Solving these eqns, we get
k = 100 and l = 80.
Therefore, number of students in class Q is 80.

Total number of cards = 1500
total columns = 45
so, total punches=1500 x 45 = 67500
for 1 hour if we make 9000 punches,
we require 67500/9000 = 7.5
so 7hours:30mins.

x = √8 - √7 = 1/(√8 + √7) and y = √6 - √5 = 1/(√6 + √5) and z = √10 - 3 = 1/(√10 + 3)

As (√8 + √7) > (√6 + √5), (√8 - √7) < (√6 - √5)

As (√10 + 3) > (√8 + √7) > (√6 + √5)

z < x < y.

A point has no dimension and a line has one dimension is the statement that best compares a line and a point.

Let 'x' be the number of new Rs.2000 notes.

Given for one new 2000 note there are three old 500 notes.

i.e, 3x

Given 10 more new Rs.2000 notes are added to the collection
and the ratio of new Rs.2000 notes to old Rs.500 notes 

x+103x=12⇒x=20

Therefore, number of new Rs.2000 notes =  x+10 = 30.

old Rs.500 notes = 3x = 60.

Thus, the total number of notes in the collection  = 30 + 60 = 90.

If virus is K in 1hr i.e 60 min
then in 57 min it was K/2 as it doubles every 3 minutes
=> In 54 min it was K/4.
At 54 minutes it was K/4.