(1)
Given:
Purchase rate (C.P.) : 8 pears for ₹ 75
Desired Gain: 20%
Total Selling Price (S.P.): ₹ 90
C.P. of 1 pear = ₹ $\frac{75}{8}$
Let us find the required S.P. of 1 pear to gain 20%:
$$\begin{aligned}\text {S.P.} = \Big( \frac{100 + \text{Gain percentage}}{100} \Big) \times \text{C.P.} \\[1em] = ₹ \Big( \frac{100 + 20}{100} \Big) \times \frac{75}{8} \\[1em] = ₹ \Big( \frac{120}{100} \times \frac{75}{8}\Big) \\[1em] = ₹ \Big( \frac{15}{100} \times \frac{75}{1}\Big) \\[1em] = ₹ \Big( \frac{15}{4} \times \frac{3}{1}\Big) \\[1em] = ₹ \Big( \frac{45}{4}\Big) \\[1em] = ₹ 11.25\end{aligned}$$
S.P. of 1 pear = ₹ 11.25
Now, let us calculate how many pears to sell for ₹ 90:
Number of pears = $\frac{\text{Total S.P.}}{\text{S.P. of 1}}$
Number of pears = $\frac{90}{11.25} = 8$
Hence, option 3 is the correct option.
(2)
Given:
Wholesale C.P. (for everyone): 8 pears for ₹ 75
Ghanshyam’s S.P. rate : 9 pears for ₹ 90
⇒ S.P. of 1 pear = ₹ $\frac{90}{9} = ₹ 10$
C.P. of 1 pear = ₹ $\frac{75}{8} = ₹ 9.375 \quad \text{[From previous step]}$
Gain per pear = S.P. - C.P.
Gain per pear = ₹ 10 - ₹ 9.375 = ₹ 0.625
And
Gain% = $\Big(\frac{\text{Gain}}{\text{C.P.}} \times 100\Big)$%
= $\Big(\frac{0.625}{9.375} \times 100\Big)$%
= $\Big(\frac{1}{15} \times 100\Big)$% $\quad$ [Dividing 0.625 and 9.375 by 0.625]
= $\Big(\frac{1}{3} \times 20\Big)$% $\quad$ [Dividing 100 and 15 by 5]
= $6\frac{2}{3}$%
Hence, option 1 is the correct option.
(3)
Given:
C.P. of 8 pears = ₹ 75
S.P. of 8 pears = ₹ 90
Gain = S.P. - C.P.
Gain = ₹ 90 - ₹ 75 = ₹ 15
And
Gain% = $\Big(\frac{\text{Gain}}{\text{C.P.}} \times 100\Big)$%
= $\Big(\frac{15}{75} \times 100\Big)$%
= $\Big(\frac{1}{5} \times 100\Big)$% $\quad$ [Dividing 15 and 75 by 15]
= $\Big(\frac{1}{1} \times 20\Big)$% $\quad$ [Dividing 100 and 5 by 5]
= 20%
Hence, option 3 is the correct option.
(4)
Given:
Total pears = 120
Rotten pears = 24
Wholesale (C.P.) : 8 for ₹ 75
⇒ C.P. of 1 pear = ₹ $\frac{75}{8}$
Selling rate : 8 for ₹ 90
⇒ S.P. of 1 pear = ₹ $\frac{90}{8}$
Let us find Total C.P. of 120 pears:
Total C.P. = (C.P. of 1 pear) x (Total number of pears)
Total C.P. = $\frac{75}{8} \times 120$
Total C.P. = 75 x 15 = ₹ 1125
Now, let us find Total S.P. of remaining pears:
Remaining pears = 120 - 24 = 96
Total S.P. = (S.P. of 1 pear) x (Remaining pears)
Total S.P. = $\frac{90}{8} \times 96$
Total S.P. = 90 x 12 = ₹ 1080
Since C.P. > S.P., there is a loss.
Loss = C.P. - S.P.
Loss = ₹ 1125 - ₹ 1080 = ₹ 45
And
Loss% = $\Big(\frac{\text{Loss}}{\text{C.P.}} \times 100\Big)$%
= $\Big(\frac{45}{1125} \times 100\Big)$%
= $\Big(\frac{1}{25} \times 100\Big)$% $\quad$ [Dividing 45 and 1125 by 45]
= $\Big(\frac{1}{1} \times 4\Big)$% $\quad$ [Dividing 100 and 25 by 25]
= 4%
Hence, option 2 is the correct option.