Question:

MATH question plz help!!!?

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ok its a pretty easy math question but i still don't understand them there is two of them

1) the sides of a rectangle are in the ration 3:2. what is the length of each side if the perimeter of the rectangle is 55 cm.

and number 2 is

2) the sum of three consecutive integers is 90

a)find the 3 numbers by letting x represent the first integer.

b)find the three numbers by letting x represent the second integer.

plz help me and also try to explain how you got the answer

thank you

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2 ANSWERS


  1. 1)

    Let 'l' be the length of the rectangle.

    Let 'b' be the breadth of the rectangle.

    l : b = 3 : 2, which can also be written as:

    (l / b) = (3 / 2).

    => l = (3b / 2).

    The perimeter of the rectangle is 2(l + b) = 55.

    => 2[(3b / 2) + b] = 55.

    => 2[(3b + 2b)/2] = 55.

    => (3b + 2b) = 55.

    => b = 55/5 = 11.

    So, breadth = 11 cm.

    =>  l = (3b / 2) as written above. So, l =  (33 / 2), => 16.5

    So, length of the rectangle is 16.5 cm and breadth of the rectangle is 5 cm.

    _____________________________________

    2)

    a)Let the first number be 'x'. Since the numbers are consecutive, they're (x), (x+1), (x+2) [ WRITTEN IN TERMS OF 'x', being the first number].....

    So, (x) + (x+1) + (x+2) = 90, as the sum of the 3 consecutive numbers is 90.

    => 3x + 3 = 90.

    => 3x = 87.

    => x = 29.

    Since 'x' = 29, (x + 1) = 30, (x + 2) = 31. The 3 numbers are 29, 30, 31.

    _____________________________________

    b)

    Let the 2nd number of the 3 numbers be 'x'. So, the other two numbers are (x-1), (x+1).

    SO, the 3 numbers are (x-1), (x), (x+1)[ WRITTEN IN TERMS OF 'x', being the second integer].....

    The sum of 3 numbers is 90:

    (x-1) + (x) + (x+1) = 90.

    => 3x = 90.

    => x = 30.

    So, the second integer is 30. he other two integers are:

    (x-1) = 29.

    (x+1) = 31.

    The 3 numbers (x-1), (x), (x+1) are 29, 30, 31....

    Hope my answer was useful enough to clear your doubts.


  2. part 1:

    3:2 is the ratio = 3/2(fraction)=1.5

    rectangle has 4 sides(4 unknowns represented with x)...2 sides being longer than the other 2 sides

    so the 2 longer sides is represented by 3/2x

    and the 2 shorter sides is represented by x

    add all the x's up:

    x+x+3/2x+3/2x=5x

    solve for x

    5x=55

    x=55/5

    x=11

    plug in 11 for x.....3/2*11= 16.5

    check your answer:

    11+11+16.5+16.5= 55  

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