Page 180 - Start Up Mathematics_8 (Non CCE)

S.P. of the computer = ` 28,700
Since S.P. > C.P., there is a gain.

Gain = S.P. – C.P. = ` (28,700 – 27,000) = ` 1,700
,
Ê Gain ˆ Ê 1 700 ˆ
Gain% = Á C.P. ¥100 % = Á Ë 27 000 ¥100 % = 6.29%
˜
˜
¯
Ë
¯
,
Hence, Sangeeta made a profit of 6.29%.
Example 3: If the cost price of 14 apples is the same as the selling price of 12 apples, find the gain or
loss percent.
Solution: Let the C.P. of each apple be ` 1.
Then, C.P. of 12 apples = ` 12
and C.P. of 14 apples = ` 14 = S.P. of 12 apples
\ S.P. of 12 apples = ` 14
Since S.P. of 12 apples > C.P. of 12 apples, there is a gain.
Gain = ` (14 – 12) = ` 2

ˆ
ˆ
Gain% = Ê Gain ¥100 % = Ê 2 ¥100 % = 16.66% = 16.7% (approx)
˜
Á
Á
˜
¯
Ë
¯
Ë12
C.P.
Hence, Gain% = 16.7%
Example 4: By selling a television set for ` 4,500, a dealer suffers a loss of 10%. Find the cost price of
the television.
Solution: S.P. of television = ` 4,500, Loss% = 10%
100 ¥S.P.
Now, C.P. =
100 - Loss%
100 4500¥ 100 4500¥
\ C.P. = = = ` 5,000
100 10- 90
Hence, the cost price of the television is ` 5,000.
Example 5: A shopkeeper bought 100 bed covers for ` 2,000 each. Due to some calculation mistake, he
sold 10 bed covers at ` 1,200 each. At what rate should he sell the remaining, so as to have
a profit of 14% on the whole?
Solution: C.P. of 1 bed cover = ` 2,000

\ C.P. of 100 bed covers = ` (100 × 2,000) = ` 2,00,000
Desired profit% = 14%
Ê 14 ˆ
\ Desired profit = 14% of 2,00,000 = ` Á 100 ¥ 200 000, , ˜ ¯ = ` 28,000
Ë
\ S.P. of 100 bed covers = ` (2,00,000 + 28,000) = ` 2,28,000
By mistake 10 bed covers were sold for ` 1,200 each.
\ S.P. of these 10 bed covers = ` (10 × 1,200) = ` 12,000

Hence, desired S.P. of remaining (100 – 10) 90 bed covers
= ` (2,28,000 – 12,000) = ` 2,16,000
216 000,,
\ S.P. of 1 bed cover = ` = ` 2,400
90

The shopkeeper should sell the remaining 90 bed covers for ` 2,400 each.
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