If the cost of x metres of wire is d rupees, then what is the cost of y metres of wire at the same rate ?

Answer: Option C

Answer: Option A

Explanation:

Less Men, means more Days {Indirect Proportion}

Let the number of days be x
then,

27 : 36 :: 18 : x
[Please pay attention, we have written 27 : 36 rather than 36 : 27, in indirect proportion, if you get it then chain rule is clear to you :)]

\begin{aligned}
x = \frac{36*18}{27} \\
x = 24
\end{aligned}
So 24 days will be required to get work done by 27 men.

Answer: Option C

Explanation:

Please always remember, that what exactly we need to calculate before applying chain formula. As in this question we need to find how many mats, RIGHT !
So we will compare everything with "number of mats"
As,

More men, More number of mats (Direct Proportion)
More days, More number of mats (Direct Proportion)

So, it can be solved as,

\begin{aligned}
\begin{bmatrix}Weavers & 4 & 8 \\Days & 4 & 8 \end{bmatrix} :: 4 : x \\

=> x*4*4 = 8*8*4 \\
=> x = 16
\end{aligned}

Answer: Option B

Explanation:

Let the time required by x seconds.
Then, More cloth means More time (Direct Proportion)
So,
\begin{aligned}
0.128 : 1 :: 25 : x
=> x = \frac{25*1}{0.128} \\
=> x = 195.31
\end{aligned}

So time will be approx 195 seconds

Answer: Option D

Explanation:

There is meal for 200 children. 150 children have taken the meal.
Remaining meal is to be catered to 50 children.
Now, 200 children = 120 men

So, 50 Children = 120/200 * 50 = 30 men