Saturday, 28 November 2015

SETS 1




If n(A)= 60 , n(AuB) = 120 and n(AnB)=10, find n(B)

Solution

n(AuB) = n(A) + n(B) - n(AnB)

  120     = 60 + n(B)  – 10

  120     = 60 -10 + n(B) 

  120     = 50 + n(B) 

  120 - 50        = n(B)

  70        = n(B)

Hence n(B) = 70 answer



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If n(A)= 66 , n(AuB) = 120 and n(AnB) = 30, find n(B).

DIFFERENCE OF 2 SQUARES 2




Evaluate 3912 – 3812

Solution

3912 – 3812 = (391 + 381)( 391 – 381)

                     = (772)( 10)

                     = 7720

3912 – 3812 = 7720

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Evaluate 5062 – 3062

ALGEBRA 1




Expand 2w(w – 7)


solution


= 2w(w – 7)

= (2w x w) – (2w x 7)

= 2w2 – 14w answer

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Expand 3a(a+ 8)

PERCENTAGE PROFIT 1




A man got a profit of 130/= after selling an item for 2600/=. Find the percentage profit.

Solution

%’ge profit = Profit   X  100    [where B. P. represents Buying Price.]
                      B.P.

%’ge profit = 130   X  100   
                    2600

%’ge profit = 5%   
                       
Hence Percentage Profit is 5%

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A man got a profit of 3400/= after selling an item for 17,000/=. Find the percentage profit.

LOGARITHMS 2




If log3(3x + 12)=4; find x

   Solution

log3(3x + 12)=4

 (3x + 12)=34   
                      
 3x + 12=81


3x = 81 – 12

3x =  69


3x =  69   
3        3

x = 23


Hence x = 23


TRY THIS...............

If log2(2x - 26)=3; find x