Question

Two angles a and b form a linear pair and 2a - 3b = ${60}^{\circ }$. Find the value of 5b.

• A. ${300}^{\circ }$
• B. ${260}^{\circ }$
• C. ${130}^{\circ }$
• D. ${340}^{\circ }$

Answer 1

The correct option is A ${300}^{\circ }$

Given that,
$2a-3b={60}^o-------\left(i\right)$
Also, if angles a and b form a linear pair, then
$a+b={180}^o$
$\Rightarrow a={180}^o-b-------\left(ii\right)$

Substituting the value of a in eq. (i), we get,
$2({180}^o-b)-3b={60}^o$
${360}^o-2b-3b={60}^o$
$5b={360}^o-{60}^o={300}^o$
Hence, the value of $5b={300}^o$