Question

a .given that x:y=5:12,find the value of x if the value of x + y =51

b .given that m:n=11:7,find the value of n if the value of m + n

Answer 1

x=5f
y=12f
5f+12f=51
17f=51
f=3
so x =15

Answer 2

Hey friend, Harish here.

Here is your answer.

a) x:y = 5:12 

x+ y = 51 (given)

Let, x=5a & y = 12a

So, 5a + 12a = 51.
 
→  17a = 51.

→  $a = \frac{51}{17}$

→ a = 3.

x = 5a = 5 × 3 = 15 

Therefore value of x is 15.
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b)  m : n = 11: 7

m+ n = 39

 Let m = 11 x & n = 7x

Then, 11x + 7x = 39
  
           18x = 39

               x = 39/18 = 13/6 

So, n = 7 x = 7 × 13/6 = 91/6.

Therefore n value is 91/6.
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Hope my answer is helpful to you.