Cost of 5 kg of wheat is Rs. 91.50.
(a) What will be the cost of 8 kg of wheat?
(b) What quantity of wheat can be purchased in Rs. 183?

Given:

The cost of $5\ kg$ of wheat is $Rs.\ 91.50$.

To do:

We have to find:

(a) The cost of $8\ kg$ of wheat.

(b) The quantity of wheat that can be purchased for $Rs.\ 183$.

Solution:

(a) The cost of $5\ kg$ wheat $=Rs.\ 91.50$

We know that,

The cost of $1\ kg$ can be obtained by dividing the given amount by the given quantity.

The cost of $1\ kg$ wheat $=\frac{91.50}{5}$

$=Rs.\ 18.30$

Therefore,

The cost of $8\ kg$ wheat $=Rs.\ 18.30\times8$

$= Rs.\ 146.40$

The cost of $8\ kg$ wheat is $Rs.\ 146.40$.

(b) The cost of $5\ kg$ wheat $=Rs.\ 91.50$

We know that,

The quantity of wheat for $Rs.\ 1$ can be obtained by dividing a given quantity by the given amount.

The quantity of wheat for $Rs.\ 1 = \frac{5}{91.50}\ kg$

Therefore, 

The quantity of wheat for $Rs.\ 183 = \frac{5}{91.50}\times183$

$= 10\ kg$

The quantity of wheat for $Rs.\ 183$ is $10\ kg$.