A person gives 30% of his income to his elder daughter and 40% of remaining to his younger daughter. And he distributes rest of the money equally among his 3 sons. If each son got Rs. 672, then how much money did the elder and younger daughter got?
$$\frac{6}{10}\frac{7}{10}x=2016$$
$$x=4800$$
Required amount=
$$\frac{30}{100}4800+\frac{7}{10}\frac{4}{10}*4800$$
=2784
However, the answer given is:
1344
Consider only percentages of the whole amount.
Elder daughter gets $30 \%$
Remainder is $70 \%$
$40 \%$ of that is $(0.4)(70) = 28 \%$ of the whole, and that's what the younger daughter gets
Total disbursed so far = $58 \%$.
Remainder = $42 \%$, so each son gets $14 \%$
$14 \%$ of the whole is Rs. $672$, which makes the whole Rs. $672(\frac{100}{14}) = 4800$.
The relevant amounts are therefore $30 \%$ of $4800$ = Rs. $1440$ (elder daughter) and $28 \%$ of $4800$ = Rs. $1344$.