Question

# A person purchases 90 clocks and sells 40 clocks at a gain of 10% and 50 clocks at a gain of 20%. If he sold all of them at a uniform profit of 15%, then he would have got Rs. 40 less. The cost price of each clock is:

A

Rs. 50

B

Rs. 60

C

Rs. 80

D

Rs. 90

E

Rs. 70

Solution

## The correct option is D Rs. 80 Let C.P. of each clock be Rs. x. Then, C.P. of 90 clocks = Rs. 90x. ∴ [(110 % of 40x) + (120% of 50x)] - (115% of 90x) = 40 ⟹ 44x + 60x - 103.5x = 40 ⟹ 0.5x = 40 ⟹ x = 80.

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