A merchant buys 200 kg of rice at $1.25 per kg, 400kg of wheat at $0.7

Rice

Total C.P.= \(200*1.25= 250\)

\(100\) kg of rice C.P = \(100*1.25= 125\)

S.P of this \(100\) Kg ( At a loss of \(25\%\)) = \(.75*125= 93.75\)


Wheat

Total C.P. = \(400*.75= 300\)

\(100 \)Kg of wheat C.P \(=100*.75= 75\)

S.P of \(100\) Kg of wheat ( at a profit of \(25\%\))= \(1.25*75= 93.75\)

Tea

Total C.P. = \(300*.5= 150\)

\(100\) Kg of tea C.P\(= 50\)

S.P of \(100\) Kg ( at a profit of \(30\%\))\(= 1.3*50=65\)

So total quantity sold so far

\(100 +100 +100 = 300\)

Quantity remaining = \(900-300=600\)

\(\frac{1}{3}\) of \(600\) was sold at $1

So \(200\) was sold at $1

Remaining = \(400 \)kg's

Total revenue so far = \(93.75 +93.75+65+ 200= 452.5\)

Trader should make a profit of \(25\%\) on the whole outlay:

Total C.P= \(250+300+150=700\)

At a profit of \(25\% \)means = \(1.25 *700 =875 \)

So total revenue should be \(875\) for a profit of \(25\%\) on the whole outlay.

However so far we have only \(= 452.5 \)

Remaining amount = \(875-452.5= 422.5\)

Also remaining quantity that we have is \(400 \)

Hence remaining quantity should be sold \(\frac{422.5}{400} \approx 1.06 \) per kg for a profit of \(25\%\) on the whole outlay.

Ans-B

Hope it's clear.

(Huff...huff...)