Question

If (3x +2y): (9x+ 5y) = 4:11, then (7x – 4y): (4x+ 5y) = ?​

Answer 1

Answer:

2 :23

Step-by-step explanation:

3x+2y = 4

9x+5y = 11

multiply with 3

9x+ 6y= 12

9x +5y=11

subtract statements

y= 1

put y= 1 in statement

x =2/3

(7x - 4y) : ( 4x +5y)

put x value and y value in above statement

( 14/3 - 4) : (8/3 +5)

14-12 /3 : 8+15 /3

2/3 : 23/3

= 2 : 23

Answer 2

Answer:

(7x – 4y): (4x+ 5y)  = 2:23

Step-by-step explanation:

Given,

(3x +2y): (9x+ 5y) = 4:11

To find,

(7x – 4y): (4x+ 5y)

Solution:

since (3x +2y): (9x+ 5y) = 4:11

$\frac{(3x +2y)}{ (9x+ 5y)}$ = $\frac{4}{11}$

Cross multiplying we get

11(3x+2y) = 4(9x+5y)

33x+22y = 36x+20y

36x-33x = 22y - 20y

3x = 2y

2y = 3x

y = $\frac{3}{2} x$  -------------------(1)

(7x – 4y): (4x+ 5y)  = $\frac{(7x - 4y)}{ (4x+ 5y) }$

Substitute the value of y from equation(1) we get

$\frac{(7x - 4y)}{ (4x+ 5y) }$ = $\frac{(7x - 4X\frac{3}{2}x )}{ (4x+ 5X\frac{3}{2}x) }$

= $\frac{(7x - 6x )}{ (4x+ \frac{15}{2}x) }$

= $\frac{x }{ \frac{23}{2}x }$

= $\frac{1}{\frac{23}{2} }$

= $\frac{2}{23}$

$\frac{(7x - 4y)}{ (4x+ 5y) }$  = $\frac{2}{23}$

∴ (7x – 4y): (4x+ 5y)  = 2:23

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