In a camp, there is a meal for 120 men or 200 children. If 150 children have taken the meal, how many men will be catered to with the remaining meal ?

Answer: Option B

Explanation:

Less shadow, Less Height (Direct Proportion)
So, let height of building be x metre
then,
\begin{aligned}
40.25 : 17.5 :: 28.75 : x \\

=> x = \frac{17.5*28.75}{40.25} \\
=> x = 12.5
\end{aligned}

So height of building should be 12.5 metre

Answer: Option C

Explanation:

Although we can first calculate the cost of one toy and then can multiply it with 40 to get the result.
but we will solve it with chain rule so that we can prepare ourself for other complex problems which we can solve easily by applying this rule.

Let the required cost be Rs. x
More toys means More Cost. (Direct Proportion)

\begin{aligned}
15:40 :: 240:x \\
=> x = \frac{240*40}{15} \\
=> x = 640
\end{aligned}

So 40 toys will cost Rs 640

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:

More Men, Less Hours {Indirect Proportion}
Less Days, More Hours {Indirect Proportion}
\begin{aligned}
\begin{bmatrix}Men & 15 & 10 \\Days & 12 & 18 \end{bmatrix} :: 6 : x \\
=> x * 15 * 12 = 10 * 18 * 6 \\
=> x = \frac{10*18*6}{15*12} \\
=> x = 6
\end{aligned}

Answer: Option A

Explanation:

Less toys, Less Price (Direct Proportion)
So, let the price be Rs. x
then,
\begin{aligned}
23:12 :: 276:x
=> x = \frac{276*12}{23} \\
=> x = 144
\end{aligned}

So price of 12 toys will be Rs. 144