Question

the cost of 3 pens is 15 rupees. then what is the rule for the cost of x pens​

Answer 1

Answer:

This is your required answer

Step-by-step explanation:

The original question is:

“If the cost of 3 pens and 5 pencils is Rs 14, then what is the cost of 10 pens and 12 pencils?”

(Rs = Indian Rupee = 1.6¢ U.S.)

I will start by saying that you should do your own homework; you are lucky I am feeling charitable tonight.

To answer the question, we need to know how much a pen costs and how much a pencil costs. For this we use some deductive reasoning:

1. Pencils are commonly less expensive than pens

2. There are 8 items, and 14 is not divisible by 8.

3. It can be assumed that the prices are in whole units (so no fractions of a Rs).

So we will separate the two groups:

5 pencils

3 pens

The minimum price of any item is 1 Rs, so if we assume the pencils cost Rs 1 each, that means that the three pens will cost Rs 9.

9 is divisible by 3, so we can determine with a fair degree of certainty that:

Each pencil costs Rs 1 and

Each pen costs Rs 3

Now it is a simple matter of multiplying 10 x 3 (pens times Rs) and adding this result to 12 x 1 (pencils x Rs):

30 + 12 = 42

So if 3 pens and five pencils cost Rs 14, then 10 pens and 12 pencils will cost Rs 42.

Answer 2

3 pens = 15₹

x pens = ?

15×x/3= 5x is cost of x pens