Question

the marks obtained for A and B is 3:4 if A get 30 marks less than b then the marks obtained by B are​

Answer 1

Let B got x marks in the test.

30 marks less than x: x-30 (A's marks)

Equating

If we write the conditions in an equation:-

$\sf{3:4=(x-30):x}$

Solving the Equation

$\sf{4(x-30)=3x}$

$\sf{4x-120=3x}$ [The distribution Law]

$\sf{4x-3x=120}$ [Transposing the Sides]

$\sf{\therefore{x=120}}$

The solution is $\sf{x=120}$. Hence B obtained 120 marks.