Quant by Arun Sharma

MBA CAT 2024
2702
kanak84 Says
page no. 22 and 23rd or the 2nd edition deals with these formulas..read these pages carefully because it covers atleast 5 question profiles


I agree kanak that it indeed has the method of solving the question and you did use the exact method perfectly well. I was just talking about the formula that is not mentioned in that book.

@EagleMenace - PMd u my ID.
2703
Some more

1) If a1, a2 ...aN are in AP where aI>0, then find the value of the expression

1/{sqrt(a1) + sqrt(a2)} + 1/{sqrt(a2) + sqrt(a3) +.... till n terms

(Note: Does anyone think that it should be n-1 terms..)

a) (1-n)/{sqrt(a1) + sqrt(aN)}

b) (n-1)/{sqrt(a1) + sqrt(aN)}


certainly it is n-1 terms
rationalise each and every term by multipying and diving by sqrt(a1)-sqrt(a2),sqrt(a2)-sqrt(a3)...and so on

now look at the denominator of each term after rationalisation...a1-a2,a2-a3,a3-a4 and so on... arent these all equal to (-d)?

ok fine now take care of nominator, it comes as sqrta1-sqrta2+sqrta2-sqrta3+sqrta3-sqrta4....+sqrta(an-1)-sqrtan (since all denominators are -d)

numerator becomes sqrta1-sqrtan

again rationalise and get numerator a1-an and denominator{-d*(sqrta1+sqrtan)

we write a1-an = -(n-1)*d

hence finally we get option b as the answer
2704
I agree kanak that it indeed has the method of solving the question and you did use the exact method perfectly well. I was just talking about the formula that is not mentioned in that book.



ok.. ...no problem
2705
Some more

2) If the first two terms of an HP are 2/5 and 12/13 respectively then which one of the following be the largest term.

a) 4th
b) 5th
c)7th
d) 8th



corresponding terms of AP are 5/2 and 13/12
common diff= 17/12

go through option and find minimum term of AP ..this will give u largest term of HP...option a.
2706
corresponding terms of AP are 5/2 and 13/12
common diff= 17/12

go through option and find minimum term of AP ..this will give u largest term of HP...option a.


Your methodology is spot on but the answer I am afraid is not 4th..it's 7th.

Pg 77 question 25.
2707

Q. The power of 5 that will exactly divide 123! is ?

a. 28 b. 30 c. 31 d.59 e. 29

Please explain the approach also, Thanks.

2708
Your methodology is spot on but the answer I am afraid is not 4th..it's 7th.

Pg 77 question 25.




@Kanak...Sent a PM
2709
Q. The power of 5 that will exactly divide 123! is ?

a. 28 b. 30 c. 31 d.59 e. 29

Please explain the approach also, Thanks.


the power of 5 that will exactly divide 123! will be the highest power of 5 in 123!

hence

123!/5 = 24

123!/25 = 4

Answer a - 28
2710
Q. The power of 5 that will exactly divide 123! is ?

a. 28 b. 30 c. 31 d.59 e. 29

Please explain the approach also, Thanks.

Its 28..If the answer is right i'll post the approach...
2711
Q. The power of 5 that will exactly divide 123! is ?

a. 28 b. 30 c. 31 d.59 e. 29

Please explain the approach also, Thanks.


ans..28

+=24+4=28

denotes greatest integer function
2712
Ganu02 Says
Its 28..If the answer is right i'll post the approach...


28 is the right answer as explained by Hector. Thanks guys.
2713

Hi Puys,

Yaar ek HP ka concept nahin samajh aa raha....

Agar koi AP hai decreasing let's say

6,4,2 ....

to iska opposite HP ho gaya

1/6,1/4,1/2

That means that this is an increasing HP.

Now if you look at the fifth term of the AP, it will be -2...and the corresponding term of HP will be -1/2

My question is...how can an increasing HP have a -ive consequent term...????

2714
Hi Puys,

Yaar ek HP ka concept nahin samajh aa raha....

Agar koi AP hai decreasing let's say

6,4,2 ....

to iska opposite HP ho gaya

1/6,1/4,1/2

That means that this is an increasing HP.

Now if you look at the fifth term of the AP, it will be -2...and the corresponding term of HP will be -1/2

My question is...how can an increasing HP have a -ive consequent term...????

Yeah it can definetely go negative... Chk out the meaning for harmonic u will realize why its called harmonic
btw harmonic progression is given by

a, a/1+d, a/1+2d, a/1+3d
2715
Hi Puys,

Yaar ek HP ka concept nahin samajh aa raha....

Agar koi AP hai decreasing let's say

6,4,2 ....

to iska opposite HP ho gaya

1/6,1/4,1/2

That means that this is an increasing HP.

Now if you look at the fifth term of the AP, it will be -2...and the corresponding term of HP will be -1/2

My question is...how can an increasing HP have a -ive consequent term...????

Progression is nothing but a series of numbers which have a certain kind of fixed relation between them. In case of AP and GP we see that the relation may lead to a series which is constantly increasing or decreasing so we can make a basic division as increasing or decreasing series. But no such relation can be dawn in case of Harmonic progression.
If we think of your series the 4th term is 0. So do we have a corresponding 4th term in HP of this series.
Also can't a series of 0's be considered as an AP series with common difference 0?(there is no HP existing for this series) or a series of 1 as AP with common difference 0 or a GP with ratio as 1?

So I just think we cannot have such division (increasing/decreasing) for the HP series.
2716
Progression is nothing but a series of numbers which have a certain kind of fixed relation between them. In case of AP and GP we see that the relation may lead to a series which is constantly increasing or decreasing so we can make a basic division as increasing or decreasing series. But no such relation can be dawn in case of Harmonic progression.
If we think of your series the 4th term is 0. So do we have a corresponding 4th term in HP of this series.
Also can't a series of 0's be considered as an AP series with common difference 0?(there is no HP existing for this series) or a series of 1 as AP with common difference 0 or a GP with ratio as 1?

So I just think we cannot have such division (increasing/decreasing) for the HP series.


dude a harmonic progression changes it sign after 0... Remember a sign wave? it changes from positive to negative right? same applies here...

PS: Googled u can refer for more here http://en.wikipedia.org/wiki/Harmonic_progression_%28mathematics%29

Edit: bhai I certainly misread on what u meant
2717
Hi guys,

This question is from Probability in Arun Sharma.Could anyone please help me out with this problem?

Out of a pack of 52 cards one is lost; from the remainder of the pack, two cards are drawn and are found to be spades. find the chance that the missing card is a spade.

a) 11/50 b) 11/49 c)10/49 d)10/50



Hi Dude,
Your answer :

When you draw 2 cards from a pack of 52 you are left with 50 cards.
Sample Space - 50 Cards.
Event - Loosing a Spade card from 50 - 11 ( Since already 2 spades have been drawn)

Chance of loosing a spade from the entire pack can be defined as

= Event/Sample Space
Ans = 11/50
Which is option (a)

Cheers!
2718
dude a harmonic progression changes it sign after 0... Remember a sign wave? it changes from positive to negative right? same applies here...

PS: Googled u can refer for more here Harmonic progression (mathematics) - Wikipedia, the free encyclopedia


Well if you move from one side of zero to the other side it will always be accompanied by a change of sign. The question was: how can an increasing HP have a -ive consequent term...???? So i just answered that not every series can be divided as an increasing or decreasing series.
2719

Hi,
Can any body gve me an elaborate soln for this one:
Q8(LOD II Profit & Loss)
A dishont dealer marks up the the price of his goods by 20 % and gives a discount of 10% to the customer.Besides , he also cheats both his supplier and his buyer by 100gms while buying or selling 1 kg.Find the percentage profit earned by the shopkeeper.
(a) 20%
(b)25%
(c)32%
(d)none of these

2720
Hi,
Can any body gve me an elaborate soln for this one:
Q8(LOD II Profit & Loss)
A dishont dealer marks up the the price of his goods by 20 % and gives a discount of 10% to the customer.Besides , he also cheats both his supplier and his buyer by 100gms while buying or selling 1 kg.Find the percentage profit earned by the shopkeeper.
(a) 20%
(b)25%
(c)32%
(d)none of these


suppose he bought 1100gm at 100rs. now he sells 900gm at=120-12= 108rs..so he sells 1100 gm at=108*1100/900 = 132

so his profit percentage=32
2721
Hi,
Can any body gve me an elaborate soln for this one:
Q8(LOD II Profit & Loss)
A dishont dealer marks up the the price of his goods by 20 % and gives a discount of 10% to the customer.Besides , he also cheats both his supplier and his buyer by 100gms while buying or selling 1 kg.Find the percentage profit earned by the shopkeeper.
(a) 20%
(b)25%
(c)32%
(d)none of these


Suppose that 1kg of goods cost Rs. x But the dealer cheats and buys 100 gm more. Thus for him 1.1 kg costs Rs. x i.e. cost price(CP) = x/1.1 Rs/Kg
Now he markup this actual price (x Rs/Kg) price by 20% i.e New Price = 1.2x
then he provide a discount of 10% i.e. New Price = 0.9*1.2x
But while selling he sells 100gm less than the quoted quantity i.e he actually sells 0.9Kg instead of 1Kg
Thus 0.9Kg is sold at Rs. (0.9*1.2x). Therefore per Kg cost is 1.2x Rs/Kg
So SP = 1.2x
Profit = (SP-CP)/CP*100
Ans = 32%