Official Quant thread for CAT 2013

MBA CAT 2024
7781
@sowmyanarayanan said:
A man borrows Rs. 6000 at 5% interest, on reducing balance, at the start of the year. If he repays Rs. 1200 at the end of each year, find the amount of loan outstanding, in Rs., at the beginning of the third year.
Rs.4155?

6000 at 5% = 6300
Repays 1200
Amount remaining = 5100
5100 at 5% = 5100 + 255 = 5355
Repays 1200
Amount remaining = 4155
7782
Three whole numbers are taken at random and multiplied. What is the probability that the units digit of the product is 1,3, 7 or 9?
7783
@sowmyanarayanan said:
A man borrows Rs. 6000 at 5% interest, on reducing balance, at the start of the year. If he repays Rs. 1200 at the end of each year, find the amount of loan outstanding, in Rs., at the beginning of the third year.
x=loan taken; k=payment at each year end.
reamining money=[[x(1.05)-k](1.05)]-k
[(1.05x-k)(1.05)]-k = (1.05)^2*x-2.05k; x=6000, k =1200.
4155


7784
@grkkrg said:
Three whole numbers are taken at random and multiplied. What is the probability that the units digit of the product is 1,3, 7 or 9?
65/729 ?
7785
@grkkrg said:
Three whole numbers are taken at random and multiplied. What is the probability that the units digit of the product is 1,3, 7 or 9?
(4/10)^3 EDIT
any odd other than 5 will satisfy the condition
Fave 4 out of 10; 3 nos=(4/10)^3


7786
@sowmyanarayanan said:
A man borrows Rs. 6000 at 5% interest, on reducing balance, at the start of the year. If he repays Rs. 1200 at the end of each year, find the amount of loan outstanding, in Rs., at the beginning of the third year.
6000+6000*5*1/100-1200=5100
5100+5100*5*1/100-1200=4155??
7787
@ananthchief said:
Cost price of 12 oranges is equal to the selling price of 9 oranges and the discount on 10 oranges is equal to profit on 5 oranges. What is the percentage point difference between the profit percentage and the discount percentage?Answer is 22.2%
12*CP=9*SP
10*D=5P

Profit percentage=100/300*100=100/3%
CP=300
SP=400
MP=x
x-400=1/2(100)
x=450
Discount percentage=50/450*100
=100/9%

Difference is 200/9%=22.22%


7788
@Harmeet89 said:
A student attempts a question paper with 5 true-false questions. He attempts the paper randomly, in no particular order. What is the probability that he gets 4 questions correct out of 5 ?
4 correct 1 incorrect
5c1*(1/2)^5 ?
7789
@Harmeet89 said:
A student attempts a question paper with 5 true-false questions. He attempts the paper randomly, in no particular order. What is the probability that he gets 4 questions correct out of 5 ?
5/32?
7790
@grkkrg said:
Three whole numbers are taken at random and multiplied. What is the probability that the units digit of the product is 1,3, 7 or 9?
8/125?
7791
@nick_baba said:
i'll go for 4sqrt(65) m/min
if u r going for 4rt65........den gud going
7792
@Harmeet89 said:
A student attempts a question paper with 5 true-false questions. He attempts the paper randomly, in no particular order. What is the probability that he gets 4 questions correct out of 5 ?
5/32?
7793
@Harmeet89 said:
A student attempts a question paper with 5 true-false questions. He attempts the paper randomly, in no particular order. What is the probability that he gets 4 questions correct out of 5 ?
5c1/2^5
7794
@Harmeet89 said:
@sowmyanarayanan Method please ?
No. of ways of choosing 4 questions: 5C4 = 5
No. of ways of answering them correctly: 1

So total no. of ways of answering them correctly is 5*1 = 5

and

No. of ways of answering 5 questions: 2^5 = 32

so 5/32
7795
@Harmeet89 said:
A student attempts a question paper with 5 true-false questions. He attempts the paper randomly, in no particular order. What is the probability that he gets 4 questions correct out of 5 ?
C(5, 4)*1/2^4*1/2=5/32
7796
@Harmeet89 said:
@@sowmyanarayanan@mailtoankitThank you. Now the additional questional is that "What is the probability of getting the 1st 4 questions right ?"
simple 1/32
7797
@grkkrg said:
Three whole numbers are taken at random and multiplied. What is the probability that the units digit of the product is 1,3, 7 or 9?
4*4*4/10*10*10??
7798
@Harmeet89 said:
@@sowmyanarayanan@mailtoankitThank you. Now the additional questional is that "What is the probability of getting the 1st 4 questions right ?"
RRRRW no arrangement
(1/2)^5
7799
@Harmeet89 said:
@@sowmyanarayanan@mailtoankitThank you. Now the additional questional is that "What is the probability of getting the 1st 4 questions right ?"
1/32
7800
XAT 2012 Q: Nikhil's mother asks him to buy 100 pieces of sweets worth Rs. 100/-. The sweet shop has 3 kinds of sweet kajubarfi, jamun and sandesh costing 10, 3 and .5 rupees respectively. If Nikhil decides to buy at least one sweet of each type how many jamuns ahould he buy?