Official Quant thread for CAT 2013

Find the 28383rd term of the series: 12345678910111213........
1) 3
2) 4
3) 9
d) 7
Plz give answer alongwith explanation.
@surajmenonv 6 is the ans..
Plz explain this Q..! Q attached.!
@amresh_maverick said:
1 > No of integral solutions of x^2 + 12 =y^42>No of ordered pairs (a,b) a^2 = b^3 +1 where a and b are Integers3>Unit digits of 7^15^16^17
OAs :


1> 4
2> 5
3> 7
@DeAdLy said:
u pasted same question again.??this was solved earlier also
Was not posted by me and there are around 20k posts here. So plz excuse me if I missed it.
Was solving a paper when I came across this question.
@DeAdLy said:
new question:
7 hoga

1st customer buys 4

2nd customer buys 2

3rd customer buys 1
@DeAdLy said:
new question:
let the quantity be x
1st person----> x/2 + 1/2
remaining = x - (x/2 + 1/2) = (x - 1)/2
2nd person----> 1/2(x-1)/2 + 1/2
remaining = (x - 1)/2 - ((x - 1)/4 + 1/2) = (x - 3)/4
3rd person = 1/2(x - 3)/4 + 1/2 = (x - 3)/4
x = 7kg ??
so 2nd option ?
the section of a solid right circular cone by a plane containing vertex and perpndiculr to base is an equilateral triangle of side 12cm.
find volume of cone ?

@ChirpiBird said:
i got 37.6 ....is it right?
Yes!!!
During the final calculation of averages, did you take 100% of the students or only 75% of students while calculating the average???
@maroof10 said:
@surajmenonv 6 is the ans..
lemme try...will post
@Exodia said:
Find the 28383rd term of the series: 12345678910111213........1) 32) 43) 9d) 7Plz give answer alongwith explanation.
3

the no is 7383 (2nd no frm left)
@shinoda said:
the section of a solid right circular cone by a plane containing vertex and perpndiculr to base is an equilateral triangle of side 12cm.find volume of cone ?
252rt3/11 ?
Consider a string of n 7s, 7777....77, into which + signs are inserted to produce an arithmetic expression. For example, 7 + 777 + 7 = 791 could be obtained from five 7s in this way. For how many values of n is it possible to insert + signs so that the resulting expression has value 7000?

(1) 105 (2) 106 (3) 108 (4) 109 (5) 111
@jashholmes said:
Yes!!!During the final calculation of averages, did you take 100% of the students or only 75% of students while calculating the average???
see, logically 100 should be taken (avg for class was askd)... but 28.20 was not in the option.
so i took 75 , people who took the test.
@mailtoankit said:
252rt3/11 ?
no..
share ur approach though.
@hedonistajay said:
Consider a string of n 7s, 7777....77, into which + signs are inserted to produce an arithmetic expression. For example, 7 + 777 + 7 = 791 could be obtained from five 7s in this way. For how many values of n is it possible to insert + signs so that the resulting expression has value 7000?(1) 105 (2) 106 (3) 108 (4) 109 (5) 111
108 values. :)
@sbharadwaj said:
Plz explain this Q..! Q attached.!
C= 4 ??


IF V be the volume of a cuboid of dimension x,y,z and A is its surface area then A/V will be equal to ?


a) (xyz)^2
b) 1/2 (1/xy + 1/xz + 1/yz )
c) 1/2 (1/x + 1/y + 1/z)
d)none
@Estallar12 said:
108 values.
approach ...
@hedonistajay said:
Consider a string of n 7s, 7777....77, into which + signs are inserted to produce an arithmetic expression. For example, 7 + 777 + 7 = 791 could be obtained from five 7s in this way. For how many values of n is it possible to insert + signs so that the resulting expression has value 7000?(1) 105 (2) 106 (3) 108 (4) 109 (5) 111
i am getting 28

but there arent any options

@Estallar12 approach?