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**Prakash Panneer****Member**- Registered: 2006-06-01
- Posts: 110

Assignment-22

1)If (2.5)^x = (0.025)^y = 10^3 then find 1/x-1/y.

2)If log 2 = 0.3010 then find the number of digits in 1024^1024.

3)If log 3 = a , log 2 = b then express log 5 6 interms of 'a' and 'b' .

4)If n is a positive integer then show that (1111111.....1111) - (222222.....2222) is the square of positive integer. 2n times n times

5)Out of a group of 20 teachers in a school, 10 teach Mathematics, 9 Physics and 7 Chemistry, 4 teach Math's and Physics and none teach both Math's and Chemistry. How many teach physics only?

6)If X is a finite set . Let P(X) denote the set of all subsets of X and n(X) denote the number of elements in X . If for two finite subsets A, B, n(p(A)) = n(p(B)) + 15. Then find n(B) and n(A).

7)If n(U) = 60, n(A) = 21, n(B) = 43 then find (i) Greatest value of n ( A U B )

(ii)Least value of n (AUB)

(iii) Greatest value of n ( A ∩ B )

(iv)Least value of n (A∩B)

8)If n(A) = 50, n(B) = 20 and n(A ∩B) = 10 then find n ( A U B ) ,

n ( A - B ), n ( A ∆ B ).

9)Find the number of integral solutions of x^2-y^2=2006.

10)Find the number of positive integers less than one million whch the digts 5,6,7,8,9,0 do not appear.

Thanks in Advance

Letter, number, arts and science

of living kinds, both are the eyes.

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**Ricky****Moderator**- Registered: 2005-12-04
- Posts: 3,791

Prakash, you have consistently just posted problems to this forum without showing any attempt to do them yourself. Please, if you wish to recieve help, show you've done some work and ask specific questions.

We are here to help. We are not here to do your work for you.

"In the real world, this would be a problem. But in mathematics, we can just define a place where this problem doesn't exist. So we'll go ahead and do that now..."

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**Devantè****Real Member**- Registered: 2006-07-14
- Posts: 6,400

It's nature's way for people to ask for help without having an attempt first. And we are here to block that force of nature.

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**emmajane****Member**- Registered: 2006-11-08
- Posts: 1

Please Help I have numbers 4 5 5 7 (can use only once Any way add, subtract, multiply or divide) needs to equal 24

I have done everything but only come up with 25 once & 26 several times. how do I get to 24?

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**mathsyperson****Moderator**- Registered: 2005-06-22
- Posts: 4,900

[7-(5/5)]*4 = 24

Why did the vector cross the road?

It wanted to be normal.

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