Question

Two angles $aandb$ form a linear pair, and $2a-3b={60}^{\circ }$ then $5b=$___ degrees.

Answer 1

Given that,

$2a-3b={60}^{\circ }$

Also if they form a linear pair, then

$2\times ({180}^{\circ }-b)-3b={60}^{\circ }$ $\because (a={180}^{\circ }-b)$

$\Rightarrow {360}^{\circ }-2b-3b={60}^{\circ }$

$\Rightarrow 5b={300}^{\circ }$