Question

4) 55
12. 5a + 3b : 4a + 7b = 3 : 4 అయితే a : b
ఎ) 25
ఎంత?
1) 9 : 8 2) 7:11_3) 8 : 9 4) 11 :9​

Answer 1

Answer:

a:b=8ab: 11ab =7. a:b= 8+11+7= a:b=25

Answer 2

Answer:

1) 9 : 8

Step-by-step explanation:

Given,

5a + 3b:4a+7b = 3:4

We havw to find a:b

let's say

5a + 3b = 3 .....(1)

4a + 7b= 4....(2)

multiply eq (1) by 7 and eq (2) by 3,

35a + 21b = 21 ....(3)

12a + 21b = 12 ....(4)

by subtracting  eq (4) from (3), we will get

23a = 9

$=>\ a\ =\ \dfrac{9}{23}$

put the value of a in equation (1), we will get

$5\times \dfrac{9}{23}\ +\ 3b\ =\ 3$

$=>\ b\ =\ \dfrac{8}{23}$

now,

$\dfrac{a}{b}\ =\ \dfrac{\dfrac{9}{23}}{\dfrac{8}{23}}$

$=\dfrac{9}{8}$

Hence, the ratio of a and b is give by 9:8