Search found 12 matches
You guys used combination formula. Could u specify when should I use permutation and when to use combination. Something like a rule of thumb. I understand that permutation is used when order is important. Thank u all for helping me out.
- by MubbashirAbbas
Sat May 26, 2012 11:05 am- Forum: Problem Solving
- Topic: Probability problem
- Replies: 9
- Views: 1454
- by MubbashirAbbas
Sat May 26, 2012 7:43 am- Forum: Problem Solving
- Topic: Probability problem
- Replies: 9
- Views: 1454
Probability problem
From a group of 5 girls and 4 boys, 7 are to be randomly selected. what is the probability that 4 girls will be selected.
A) 4/9 B) 3/5 C) 5/9 D) NONE OF THESE
- by MubbashirAbbas
Sat May 26, 2012 7:24 am- Forum: Problem Solving
- Topic: Probability problem
- Replies: 9
- Views: 1454
Algebra Problem
If 1/x + 1/y = 5 , and xy = 6 , then (x+y)^2 = ?
A) 800 B) 900 C) 880 D) 9800
Explanation will be appreciated. B/W is there a way i can appreciate someone's answer here. I mean give somebody a point for their contribution ???
- by MubbashirAbbas
Fri May 25, 2012 10:31 am- Forum: Problem Solving
- Topic: Algebra Problem
- Replies: 2
- Views: 987
- by MubbashirAbbas
Fri May 25, 2012 10:22 am- Forum: Problem Solving
- Topic: Tough standard deviation problem
- Replies: 3
- Views: 1554
Tough standard deviation problem
A battery manufacturer claims that the mean life of its batteries is 5 yrs with the standard deviation of 10 months. If a particular battery chosen at random lasted only 37 months, what is the chance that the manufacturer's claims are false, based on the evidence, as well as on the fact that battery...
- by MubbashirAbbas
Fri May 25, 2012 5:35 am- Forum: Problem Solving
- Topic: Tough standard deviation problem
- Replies: 3
- Views: 1554
Ronnie,
How did you come up with the answer. Did you solve the equations or did you apply some shortcut method to arrive at the conclusion. Whatever it is, Please explain the steps..
- by MubbashirAbbas
Thu May 24, 2012 11:36 am- Forum: Problem Solving
- Topic: Equations - Number of solutions
- Replies: 5
- Views: 1875
Equations - Number of solutions
Given the system of linear equations
a) x + 2y + 3z =0
b) 4x+ 5y + 6z =0
c) 7x+ 8y + 9z =0
The system has
1) has Infinietly many solutions
2) has Exactly one solution
3) has trivial solution
4) has no solution
Please explain how this can be solved
- by MubbashirAbbas
Thu May 24, 2012 4:56 am- Forum: Problem Solving
- Topic: Equations - Number of solutions
- Replies: 5
- Views: 1875
- by MubbashirAbbas
Wed May 23, 2012 10:55 am- Forum: Problem Solving
- Topic: Average problem
- Replies: 3
- Views: 936
Anil,
Could u please mention the logic. You added the first two and subtracted the last. Please explain why ?
- by MubbashirAbbas
Wed May 23, 2012 10:54 am- Forum: Problem Solving
- Topic: Average problem
- Replies: 3
- Views: 936
Average problem
In a set of four numbers, the average of the first two numbers is 50, average of last two is 80 and average of middle two is 100. What is the average of the first and last number ??
A) 60 b) 45 c) 30 d)15
- by MubbashirAbbas
Wed May 23, 2012 10:29 am- Forum: Problem Solving
- Topic: Average problem
- Replies: 3
- Views: 936
Tough quadratic equation roots problem
It is known that x^2 - 11x + 4c =0 has two distinct roots. I is also known that one factor is (X-C) and C is greater than zero. The larger root of the equation is ?
A) 4 B) 7 C) 11 D) None of these
Please help me solve this ...
- by MubbashirAbbas
Wed May 23, 2012 10:03 am- Forum: Problem Solving
- Topic: Tough quadratic equation roots problem
- Replies: 2
- Views: 11054