Page 183 - Start Up Mathematics_8 (Non CCE)

\ S.P. for Kirti = Ê 100 + Profit%ˆ ˜ ¯ C.P.¥ = ` Á Ê Ë 100 5+ ˆ ˜ ¥ 6 x
Á
100 ¯
5
Ë
100
Ê 105 6 ˆ 126
= ` Á ¥ x = ` x
˜
Ë
5 ¯
S.P. for Kirti = C.P. for Muskan 100 100
126x
fi = 441
100
441 100¥
fi x = = 350
126
Hence, C.P. of the wrist watch = ` 350
Alternate Method
Let the C.P. of the wrist watch be ` 100.

Honey’s profit % = 20%
20
Profit = ¥ 100 = ` 20
100

S.P. for Honey = ` 120
C.P. for Kirti = S.P. for Honey = ` 120
Kirti’s profit = 5%
5
fi Profit = 5% of 120 = × 120 = ` 6
100
S.P. for Kirti = ` (120 + 6) = ` 126
C.P. for Muskan = S.P. for Kirti = ` 126

If C.P. for Muskan = ` 126, actual C.P. of wrist watch = ` 100
100
If C.P. for Muskan = ` 1, actual C.P. of wrist watch = `
126

Ê 100 ˆ
If C.P. for Muskan = ` 441, actual C.P. of wrist watch = ` Á Ë 126 ¥ 441 = ` 350
˜
¯
Hence, the C.P. of wrist watch = ` 350
Example 11: Coffee costing ` 250 per kg was mixed with chicory costing ` 75 per kg in the ratio 5 : 2 for
a certain blend. If the mixture was sold at ` 230 per kg, find the profit or loss percent.
Solution: As coffee and chicory are mixed in the ratio 5 : 2, so let us assume that 5 kg of coffee is
mixed with 2 kg of chicory.
Now, C.P. of 1 kg coffee = ` 250

\ C.P. of 5 kg coffee = ` (250 × 5) = ` 1,250
C.P. of 1 kg chicory = ` 75
\ C.P. of 2 kg chicory = ` (75 × 2) = ` 150
\ Total C.P. of (5 + 2) 7 kg of mixture = ` 1,250 + ` 150 = ` 1,400
S.P. of 1 kg mixture = ` 230

\ S.P. of 7 kg mixture = ` (230 × 7) = ` 1,610
Since S.P. > C.P., there is a profit.

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