Thank you for reporting, we will resolve it shortly
Q.
Two blocks of masses $8 \,kg$ and $12\, kg$ are connected at the two ends of a light inextensible string. The string passes over a frictionless pulley. The acceleration of the system is
Let $a$ be the common acceleration of the system and $T$ be tension of the string. The equations of motion of two blocks are
$T-8g=8a$ $\quad\ldots\left(i\right)$
and $12g-T=12a$ $\quad\ldots\left(ii\right)$
Adding (i) and (ii), we get
$4g=20a$ $\quad$ or $ a=\frac{g}{5}$