I guess soln ye hoga
=(1-.41)(1-.612)(1-.355)(1-.520)
P.S. > XAT k ques yahi solv karlo ki fark penda hai

yes you are right but i wanted to ask why it cant be

prob= 1- prob of crime happening in any of the area
= 1- .41*.612*.355*.520

what is the concept?

I had a question as under which appeared in XAT2011:

The Scheduling Officer for a local police is trying to schedule additional patrol units in each of two neighbourhoods - southern and northern. She knows that any of the given day, the probablities of major and minor crimes committed in the northern neighbourhood were .418 & .612 respectively , and that the corresponding probablities in the southern neighbourhood were .355 and .520.
Assuming that all crime occur independent of each other and likewise the crime in the two neighbourhood occur independent of each other, what is the probability that no crime of either type is committed in either neighbourhood on any given day?

the soln is given prob=(1-.41(1-.612)(1-.355)(1-.520)

why can't we first find the prob of crime committed and then calculate prob of crime not committed?

i.e prob={1-(.41(.612)(.355)(.520)]

can anybody explain the concept behind this and also share the link where xat questions can be discussed?

thanks in advance

set 145

2)3
4)2

set 144

1) b
2)b
3)a

One from Probability -
There are 15 apples in a bucket out of which 6 are rotten. Each day you take out one apple from the bucket. What is the probability that after 4 days exactly 3 rotten apples are there ?
One Data Sufficiency -
Is X the father of Y?
A: X is the aunt of Z
B: Y is the son of X who in turn is the grandparent of Z.

for the first part prob= (6/15)*(5/14)*(4/13)*(9/12)


for the 2nd ques both together are also not sufficient.

set 120

1)b
2)c
3)a
4)a
5)d

Prince works in a company where his remuneration for the nth day is Rs.(n^2+2), where 'n' is the number of days for which he has worked in the company. He does not spend any money on the first three days of his job. However, from the 4th day onwards he starts spending Rs. (n + 14) on the nth
day. On which day would he save more than Rs.100 for the first time?

(a) 10th (b) 11th (c) 12th (d) 13th

12 th day


144+2 - 12+14 >100

set 107

1)4 (i think use of responsible is correct but the word "contest" is wrong should have been "context")
2)1 but confused about sentence (b) whether writing direct speech and using "declared" instead of "said"

also can anybody explain the use of "can" here in sentence c... bit confused about usage of "can" and "could"

cause the sentence is present perfect so shouldnt it should be could??

and also the use of adverb "only",,is it placed in the right position ,,shouldnt it be can "only"

3)1
4)3 not sure about sentence A but doesnt look good

this set will clear lots of doubts even if i got the answers wrong;)