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

TRY THIS…………………………….

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

TRY THIS…………….

Evaluate 506² – 306²

ALGEBRA 1

Expand 2w(w – 7)

solution

= 2w(w – 7)

= (2w x w) – (2w x 7)

= 2w² – 14w answer

TRY THIS………..

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%

TRY THIS……………………………

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