Question

'A' sells an article to 'B' at a gain of 20% and 'B' sells it to 'C' at a gain of 10% and 'C' sells it to 'D' at a gain of $12\frac{1}{2}$. If 'D' pays Rs 29.70 what did it cost to 'A'?

• A. Rs 20
• B. Rs 24
• C. Rs 18
• D. Rs 33
• E. None of the above

Answer 1

The correct option is A Rs 20

Here, $m=20n=10,p=\frac{25}{2},$
$z=Rs29.70$
$\therefore$ Cost price of A
$=\left[\frac{{100}^{3}z}{(100+m)(100+n)(100+p)}\right]=\left(\frac{100\times 100\times 100\times 29.70\times 2}{120\times 110\times 225}\right)=\left(\frac{100\times 100\times 100\times 29.70\times }{120\times 110\times 225}\right)=Rs20$