Question

If the cost price of 15 pens is equal to selling price of 20 pens find the loss %

Answer 1

GIVEN :-

• C.P if 15 pens = S.P of 20 pens.

TO FIND :-

• Loss %.

SOLUTION :-

◉ Let the C.P of 1 pen be x.

➫ C.P of 15 pens = x × 15 = 15x.

☯ ACCORDING TO QUESTION,

☛ As in the question it is given that C.P if 15 pens = S.P of 20 pens.

☛ S.P of 20 pens = 15x

➫ S.P of 1 pen = 15x/20

➫ 3x/4

Hence the S.P of 1 pen is 3x/4.

☛ Loss = C.P (1 pen) - S.P (1 pen)

➫ x - 3x/4

➫ (4x - 3x)4

➫ x/4

Hence the loss is x/4.

☛ Loss % = [Loss/C.P × 100] %

➫ [(x/4)/x × 100] %

➫ [100/4] %

➫ 25 %

Hence the Loss % is 25 %.

Answer 2

Given :-

• C.P of 15 pens = S.P of 20 pens

To Find :-

• Loss = ?

Solution :-

Let's assume C.P of 15 pens be x

➙ C.P of 15 pens = 15x

We have been told in Question,

➙ C.P of 15 pens (15x) = S.P of 20 pens

So,

$➙ \: s.p \: of \: 1 \: pen \: = \frac{\cancel{15x}}{\cancel{20}}$

$➙ \: s.p \: of \: 1 \: pen \: = \frac{3x}{4}$

⛬ S.P of 1 pen is 3x / 4

Now,

We know Formula of Loss,

$✓ \: loss = c.p \: - \: s.p$

Placing Values,

$➙ \: l = x - \frac{3x}{4}$

$➙ \: l = (4x - 3</em><em>x</em><em>) \times 4$

$➙ \: l = \frac{x}{4}$

⛬ Loss is x/4

Now,

We can apply those value in our Final Formula for Loss %

$✓ \: loss = ( \frac{loss}{c.p} \times 100)$

Placing Values,

$➙ \: loss = ( \frac{ \frac{x}{4} }{x} \times 100)$

$➙ \: loss = \frac{\cancel{100}}{\cancel{4}}$

$➙ \: loss = 25</em><em>%</em><em>$

⛬ Loss of Pen is 25%