Question

In solving an equation of the form $ax+b=0$ (a,b having only 1 as the common factor ), $A$ made a mistake in copying $b$ and got $\frac{7}{3}$ as the root whereas $B$ made a mistake in copying $a$ and got $\frac{8}{5}$ as the root . The correct root is

• A. $\frac{7}{5}$
• B. $\frac{3}{8}$
• C. $\frac{8}{3}$
• D. $\frac{8}{5}$

Answer 1

Answer: (C)

$\frac{8}{3}$

$ax+b=0$, (a, b having only 1 as the common factor)
$A$ made a mistake in copying b and got $\frac{7}{3}$
$\therefore x=-\frac{b}{a}=\frac{7}{3}$

$\therefore a=+3$

$B$ made a mistake in copying a and got $\frac{8}{5}$
$\therefore x=-\frac{b}{a}=\frac{8}{5}$

$\therefore b=-8$
Hence, correct root =-$\frac{b}{a}=\frac{8}{3}$