Linear Equations in One Variable — Maths STD 7 — Question

Let the smaller angle be $x.$
Then,The larger angle $= (x + 20^\circ )$
As, the sum of the two complementary angles is always $90^\circ .$
$\Rightarrow x + (x + 20^\circ ) = 90^\circ $
$\Rightarrow 2x + 20^\circ = 90^\circ $
$\Rightarrow 2x = 90^\circ - 20^\circ $
$\Rightarrow 2x = 70^\circ $
$\Rightarrow\text{x}=\frac{70^\circ}{2} ($By transposing $2$ to $\text{R.H.S.)}$
$\therefore\text{x}=35^\circ$
So, the smaller angle is $35^\circ .$
Hence, the correct alternative is option $(d).$