PERIMETER 1

Area of a rectangle is 84 cm². Find its perimeter if its width is 7cm.

Solution

First we find length

A =  l  x w

84 =  l  x 7

84 = 7l

7       7

12 =  l

Now length is 12cm.

We can find perimeter since we have both length and width.     

Let l = length and w = width;

P = 2(l + w)

   = 2(12 + 7)

   = 2 x 19

   = 38

Hence perimeter is 38 cm. 

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Area of a rectangle is 72 cm². Find its perimeter if its width is 4cm.

ALGEBRA 1

If │2x – 7 │= 17; Find  x

Solution

±(2x – 11 )= 17

2x -11= 17    OR   –(2x-11) = 17

2x – 11 = 17    OR   -2x+11=17

2x = 17 + 11    OR   -2x= 17-11

2x = 28     OR   -2x  =   6

2      2                -2        -2

x = 14  OR  x = -3

Hence x = 14 OR x = -3

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If │2x – 7 │= 35; Find x

EXPAND 1

Expand -10(y – 5)

Solution

= -10(y – 5)

= (-10 x y) – (-10 x 5)

= 10y – ^-50 answer

= 10y + ⁺50

= 10y + 50 answer

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Expand ^-8(W– 9)

SETS 1

If n(A)= 90 , n(B)= 100 and n(AnB)=50, find n(AuB).

Solution

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

             = 90 + 100 – 50

             = 190– 50

             = 140

Hence n(AuB) = 140 answer

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If n(A)= 140 , n(B)= 150 and n(AnB)=100, find n(AuB).

SIMPLE INTEREST 1

Angloma deposited the amount of 110,000/= in a bank which gives an interest rate of 5% for 5 years. Find the simple interest she got?

Solution

I = ?,  P = 110,000/=, T = 5 years, R = 5%

I  = PRT

      100

I  = 110,000 x 5 x 5

            100

I  = 110000 x 5 x 5

            100

I  = 1100 x 5 x 5

          

I  = 275,000/=

Hence the simple interest was Tsh 275,000/=

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Jelna deposited the amount of 18000/= in a bank which gives an interest rate of 3% for 5years. Find the simple interest she got?