Question

The price of a pen and a pencil is * 35. The pen was
sold at a 20% profit and the pencil at a 10% loss.
If in the transaction a man gains 4, how much is
cost price of the pen?
(a) 10
(b) 25
(c) 20
(d) None of these​

Answer 1

Step-by-step explanation:

Let price of pen wa Rs. X and Pencil was Rs. Y.

So,

X + Y = 35 ------------------------------ (1)

SP of Pen,

= X + 20% of X = 1.2X

SP of Pencil,

= Y - 10% of Y = 0.9Y

Man gains Rs. 4 in transaction.

It means,

Total SP = 35 + 4 = 39

Now,

1.2X + 0.9Y = 39 --------------------------- (2)

On multiplying euqation (1) by 1.2, we get,

1.2X + 1.2 Y = 42 --------------------------- (3)

Equation (3) - (2)

1.2X + 1.2Y - 1.2X - 0.9Y = 42 - 39

0.3Y = 3

Y = 10.

CP of Pencil = Rs. 10

CP of Pen = 35 - 10 = Rs. 25.

Hence, option c ) 25 is the correct answer

Answer 2

Answer:

CP of pen = 25

Step-by-step explanation:

price of a pen and a pencil = 35

CP =35

he gains 4

so SP = 39

if price of pen = 25 , when sold at 20% profit = 30, 25 *20/100 = 5

SP = 30 ( CP = 25 + 5 PROFIT)

so CP of pencil = 35 - 25 = 10, sold at loss of 10%

10 * 10/100 = 1rs loss

so SP of pencil = 9