Question Detail

If the price of 23 toys is 276, then what will the price of 12 toys ?

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

1. In a dairy farm, 40 cows eat 40 bags of husk in 40 days. In how many days one cow will eat one bag of husk ?

34 days
40 days
46 days
50 days

Answer: Option B

Explanation:

Less Cows, More days (Indirect Proportion)
Less bags, Less days (Direct Proportion)

\begin{aligned}
\begin{bmatrix}Cows & 1 & 40 \\Bags & 40 & 1 \end{bmatrix} :: 40 : x \\
=> x * 40 * 1= 40 * 1 * 40 \\
=> x = 40
\end{aligned}

2. 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 ?

xd
yd
yd/x
x/yd

Answer: Option C

3. 4 mat-weavers can weave 4 mats in 4 days. At the same rate, how many mats would be woven by 8 mat weavers in 8 days ?

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}

4. A flagstaff 17.5 metre high casts a shadow of length 40.25 metre. The height of building, which casts a shadow of length 28.75 metre under similar conditions will be :

12 metre
12.5 metre
13.5 metre
14 metre

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

5. If a quarter kg of potato costs 60 paise, how many paise will 200gm cost ?

45 paise
46 paise
47 paise
48 paise

Answer: Option D

Explanation:

Quarter of Kg means 250 gm

Less weight, less price (Direct Proportion)
So,
\begin{aligned}
250:200 :: 60:x \\
=> x = \frac{200*60}{250} \\
=> x = 48
\end{aligned}

So 200 gm will cost 48 paise.