Question

20. If (4x + 5): (3x +11) = 13:17, find the value of x.
21. If x : y = 3:4, find (3x + 4y): (5x + 6y).
22. If x : y = 6:11, find (8x – 3y): (3x + 2y).
+1​

Answer 1

Answer:

20) x = 2

21) 25:39

22) 3:8

Explanation

20) (4x + 5) : (3x + 11) = 13 : 17, find x

     => 4x + 5 by 3x + 11 = 13 by 17

     => 17(4x + 5) = 13(3x + 11)

     => 68x + 85 = 39x + 143

     => 68x - 39x = 143 - 85

     => 29x = 58

     => x = 58 by 29

     => x = 2

21) x : y = 3:4, find (3x + 4y): (5x + 6y)

    According to question,

    x by y = 3 by 4

    So, x = 3 and y = 4

    Therfore, (3x + 4y) by (5x + 6y) = (3 X 3 + 4 X 4) by (5 X 3 + 6 X 4)

    = (9 + 16) by (15 + 24)

    = 25 by 39

    = 25 : 39

22) x : y = 6:11, find (8x – 3y): (3x + 2y)

    According to question,

    x by y = 6 by 11

    So, x = 6 and y = 11

    Therfore, (8x - 3y) by (3x + 2y) = (8 X 6 - 3 X 11) by (3 X 6 + 2 X 11)

    = (48 - 33) by (18 + 22)

    = 3 by 8

    = 3 : 8

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