Three types of wheat of Rs 1 27 Rs 1 29 and Rs 1 32 per kg are mixed together to be sold at Rs 1 30 ...........

Explanation:

Let's say three variety of whet are w1( Rs. 1.27), w2( Rs.1.29) and w3( Rs. 1.32).

We first deal with type of wheat of Rs. 1.27 (w1), Rs.1.32.(w3) to get mean price Rs. 1.30

In order to make calculations easier we multiply every number by 100. Since we are working on ratios, it won't finally change the answer.

Thus, wheat1 (w1) and wheat2 (w3) are in the ratio,

w1                 w3
 127                 132
        \                 /
           mean
            130
         /                \
(130−132)    :   (127−130)
     −2                     −3

⇒w1:w3 = 2:3

Now, lets take the wheat of Rs. 1.29 (w2), Rs. 1.32  (w3). to get mean price Rs. 1.30

 w2                 w3
 129                  132
        \                /
           mean
            130
         /                 \
(130−132)     :    (129−130)
     −2                      −1

⇒w2:w3=2:1

Thus, final ratio,

⇒w1:w2:w3=2:2:(3+1)

⇒w1:w2:w3=1:1:2

Hence, option 2 is the correct answer.