$30$ women do half of the total work in $30$ days. How many more women will be required to complete the remaining work in $10$ days?

We can use the work-equivalence formula:
$$\frac{M_1\times D_1}{W_1}=\frac{M_2\times D_2}{W_2}$$
Given:$M_1=30$ women$D_1=30$ days$W_1=0.5$ (half of the total work)$D_2=10$ days$W_2=0.5$ (the remaining half of the work)Since $W_1=W_2$, the work terms cancel out:
$$M_1\times D_1=M_2\times D_2$$
$$30\times 30=M_2\times 10$$
$$900=10M_2$$
$$M_2=90$$
Total women required to complete the remaining work in $10$ days is $90$.
$$\text{More women required}=M_2-M_1=90-30=60$$