Question

the cost of 20 pens is 300 . what will be the cost of 15 such pens

Answer 1

ANSWER :

• ★ If the cost of 20 pens is Rs. 300; then the cost of 15 such pens will be Rs. 225.

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SOLUTION :

❒ Given :-

• Cost of 20 pens = Rs. 300

❒ To Find :-

• Cost of 15 pens = ?

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❒ Method 1 :-

Suppose,

• Cost of one pen = Rs. x

So,

• Cost of 20 pens will be Rs. 20 x

• Cost of 15 pens will be Rs. 15 x

It is given that,

• Cost of 20 pens = Rs. 300

According to question,

• ✪ 20 x = 300

➜ x = $\sf{\dfrac{300}{20}}$

∴ x = 15

• Thus, Cost of one pen = Rs. x = Rs. 15

∴ Cost of 15 pens = Rs. 15 x

➜ Cost of 15 pens = Rs. (15 × 15)

➜ Cost of 15 pens = Rs. 225

• Hence, cost of 15 pens will be Rs. 225.

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❒ Method 2 :-

Given that,

• ✪ Cost of 20 pens = Rs. 300

∴ Cost of 1 pen = $\sf{\dfrac{300}{20}}$

➜ Cost of 1 pen = Rs. 15

∴ Cost of 15 pens = Rs. 15 × 15

➜ Cost of 15 pens = Rs. 225

• Hence, cost of 15 pens will be Rs. 225.

Answer 2

Ꭺɳśωεɾ :

✿ Given

Cost of 20 pens = Rs. 300

✿To Find

Cost of 15 pens = ?

✿Solution

⇒Cost of 20 pens will be Rs. 20 x

⇒Cost of 15 pens will be Rs. 15 x

✿It is given that,

⇒Cost of 20 pens = Rs. 300

⇒ 20 x = 300

⇒ x = 300/20

∴ x = 15

Thus, Cost of one pen = Rs. x = Rs. 15

∴ Cost of 15 pens = Rs. 15 x

⇒Cost of 15 pens = Rs. (15 × 15)

⇒ Cost of 15 pens = Rs. 225

Hence, cost of 15 pens will be RS = 225

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