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How come sum of children = N * (x + (N-1)*3/2)? (N-1)*3/2 ?? or it should be (N-1)*3 : the formula for AP series is n (a + (n-1)*d/2) where n=number of terms a first term d common difference and this question had one add and other even choices...so i also started by putting 5 in the equation which ...

by uttam.albela

Thu Oct 22, 2009 11:15 pm
Forum: Problem Solving
Topic: Arranging the children
Replies: 5
Views: 2272

Re: Arranging the children

A group of 810 children arranged themselves in N rows for a group photograph. In each row there were 3 more children than the row ahead. Which of the following can be the value of N? a.) 6, b.) 8, c.) 5, d.) 10, e.) 12 i could solve this question by imputing the values, any other way to solve such ...

by uttam.albela

Thu Oct 22, 2009 9:41 pm
Forum: Problem Solving
Topic: Arranging the children
Replies: 5
Views: 2272

Thanks Stuart! I like your second approach than the first one. Stuart/uttam.albela, Extremely sorry for being so ignorant! :D Can you help me understand how you get 64 for each digit? hi papgust, We have 4 places for digits. (thousand place) (hundred place) (tens place) (unit place) Now how many nu...

by uttam.albela

Thu Oct 22, 2009 9:32 pm
Forum: Problem Solving
Topic: Number sequence prob
Replies: 5
Views: 1073

Re: Re-arranging letters

Out of 6 places, select 3 places. No of ways = 6C3 No. of ways to Arrange these letters DBL in selected 3 places = 3! Now we are left with 3 places where we need to put OUE in this same order. No of ways to do this = 1 So total number of ways = 6C3 * 3! * 1 = 6!/3! = 120 Let me know if any part of ...

by uttam.albela

Thu Oct 22, 2009 9:17 pm
Forum: Problem Solving
Topic: Re-arranging letters
Replies: 9
Views: 1749

Re: Progressions

1. Find the value of (100*1) + ( 99*2) + (98*3) + ...... + (2*99) + (1*100) a.) 12850 b.) 272700 c.) 23250 d.) 50500 e.) none of these 2.) Find the sum of first 20 terms of the series 1.2^2 + 2.3^2 + 3.4^2+ ..... a.) 47980 b.) 46180 c.) 47160 d.) 48180 e.) None of these Q1. General term is (101-n)*...

by uttam.albela

Thu Oct 22, 2009 9:10 pm
Forum: Problem Solving
Topic: Progressions
Replies: 2
Views: 816

Hi Abdulla, a = To reach the destination, first find out total number of ways. b = Then find out the number of ways in a particular manner mentioned in the problem. Probability = b/a problem solved :) Not let us find a and b. First a: Alicia has to cross 3 south and 3 east blocks. And, she can do t...

by uttam.albela

Thu Oct 22, 2009 8:49 pm
Forum: Problem Solving
Topic: Probability
Replies: 5
Views: 1906

Re: Inequalities

If 2x + 3y > 6 and y-x > -1 ,the sign of which of the following expressions can be uniquely determined? A. 3x + 7y B. 4x + 11y C. x+y 1.Only A and B 2.Ony B and C 3.Only C and A 4.A,B and C 5.None of these Now add 2x+3y>6 2y-2x> -2 We get 5y > 4 y> 4/5 Put this in first equation 2x > 6 - (3*(4/5)) ...

by uttam.albela

Thu Oct 22, 2009 7:58 pm
Forum: Problem Solving
Topic: Inequalities
Replies: 4
Views: 1190

Re: Number sequence prob

What is the sum of all 4-digit numbers that can be formed using the digits 1,2,3,4 where repetition of digits is allowed? Can someone give a good clear approach? In the future, please post the answer choices - the solution below will show all the steps, but it's extremely unlikely that you'd have t...

by uttam.albela

Thu Oct 22, 2009 7:42 pm
Forum: Problem Solving
Topic: Number sequence prob
Replies: 5
Views: 1073

Re: Re-arranging letters

In how many ways can the letters of the word "DOUBLE" be re-arranged such that the order in which the vowels appear in the word does not change? Solution given is 6!/3!. Why are we dividing by 3! here? Please help me understand We have 6 letters in DOUBLE, so there are 6 places to be fill...

by uttam.albela

Thu Oct 22, 2009 7:33 pm
Forum: Problem Solving
Topic: Re-arranging letters
Replies: 9
Views: 1749

Hi Abdulla, There are 10 homerooms. One of them will be with highest total. Number of ways to select one from ten homerooms. = 10C1 = 10 Now from its 8 students select 3 = 8C3 As 3 awards are of different denominations(50,30 and 20), awards can be distributed among the 3 students in = 3! Now select ...

by uttam.albela

Thu Oct 22, 2009 6:46 am
Forum: Problem Solving
Topic: Combination
Replies: 2
Views: 1561

Hi Abdulla, a = To reach the destination, first find out total number of ways. b = Then find out the number of ways in a particular manner mentioned in the problem. Probability = b/a problem solved :) Not let us find a and b. First a: Alicia has to cross 3 south and 3 east blocks. And, she can do th...

by uttam.albela

Thu Oct 22, 2009 6:25 am
Forum: Problem Solving
Topic: Probability
Replies: 5
Views: 1906

Assume salary this year = x Saving this year = s Expenditure this year = x-s Expenditure next year = s*(1+r) (Since 1 saving last year = 1+r expenditure this year s saving last year= s*(1+r) expenditure this year) Now what we have to find: saving last year / salary last year s/x = ? Given: s*(1+r) =...

by uttam.albela

Thu Oct 22, 2009 1:59 am
Forum: Problem Solving
Topic: Word Problem - Henry's income
Replies: 5
Views: 3366

Whenever you divide a series of numbers a particular number a pattern is established. For example: 5^1 / 8 remainder = 5 5^2 / 8 remainder = 1 5^ / 8 remainder = 5 this 5 , 1, 5, 1 ..... repeats 9^1 / 6 remainder = 3 9^2 / 6 remainder = 3 so the pattern is 3,3,3,3,3,3, whatever may be the power of 9...

by uttam.albela

Wed Oct 21, 2009 9:38 pm
Forum: Problem Solving
Topic: Help please
Replies: 3
Views: 975

First time = 15 - 1 = 14 Second time= 14 + 2 = 14 + 2 (1) = 16 third time = 14 + 2 + 2 = 14 + 2 (2) = 18 As the output is even all the time, u have to keep adding 2 to previous output. 99th time = 14 + 2 (how many times) From the above correlations you see that for 3rd time you have (how many times)...

by uttam.albela

Wed Oct 21, 2009 9:27 pm
Forum: Problem Solving
Topic: Any one explain please
Replies: 2
Views: 871

According to OG, When you say sqrt(p*p) whether p is negative or positive, the only answer is |P|.

if you say - (sqrt(p2)), then the answer is - |P|.

So sqrt(-x * |x|) = |X| = - x

Please refer OG maths fundamentals. sqrt(9) = 3 only.

-3 is wrong.

-sqrt(9) = -3

by uttam.albela

Wed Oct 21, 2009 9:19 pm
Forum: Problem Solving
Topic: Imp Funda - Please Help
Replies: 9
Views: 1577