Chapter 4: Q. 72 (page 404)

The sum of two number is $15$ . One number is $3$ less than the other. Find the numbers.

Short Answer

Expert verified

The required numbers are $6$ and $9$ .

Step by step solution

Step 1. Given and explanation

There are two numbers whose sum is $15$ and one number is $3$ less than the other number.

Assume the numbers to be $x, y$ .

Their sum, i.e., $15$ can be written as $x + y = 15$ .

And one number is $3$ less than the other can be written as $x = y - 3$ .

Step 2. Finding the value of first variable by substitution.

We have two equations, i.e. ,

$x + y = 15 x = y - 3$

Substituting the value of $x$ in the first equation gives us,

localid="1644337411972" $(y - 3) + y = 15 2 y = 15 + 3 2 y = 18 y = 9$

Step 3. Finding the value of other variable

Putting $y = 9$ in
$x + y = 15$ gives us,

$x + 9 = 15 x = 6$

This shows that the two numbers are $6 & 9$ .

Step 4. Check the solution.

We will check the answer by putting in both the equations. If the equations satisfy, our answers are right.

First equation is
$x + y = 15 6 + 9 = 15 15 = 15$
Hence satisfied.
Second equation is
$x = y - 3 6 = 9 - 3 6 = 6$
Hence satisfied.

Thus our answers are right.

Unlock Step-by-Step Solutions & Ace Your Exams!

Full Textbook Solutions
Get detailed explanations and key concepts
Unlimited Al creation
Al flashcards, explanations, exams and more...
Ads-free access
To over 500 millions flashcards
Money-back guarantee
We refund you if you fail your exam.

Start your free trial

Over 30 million students worldwide already upgrade their learning with Vaia!

Recommended explanations on Math Textbooks

View all explanations

What do you think about this solution?

We value your feedback to improve our textbook solutions.

The sum of two number is $15$ . One number is $3$ less than the other. Find the numbers.

Short Answer

Step by step solution

Step 1. Given and explanation

Step 2. Finding the value of first variable by substitution.

Step 3. Finding the value of other variable

Step 4. Check the solution.

One App. One Place for Learning.

Most popular questions from this chapter

Recommended explanations on Math Textbooks

Discrete Mathematics

Logic and Functions

Theoretical and Mathematical Physics

Applied Mathematics

Probability and Statistics

Mechanics Maths

Study anywhere. Anytime. Across all devices.

The sum of two number is 15. One number is 3less than the other. Find the numbers.

Short Answer

Step by step solution

Step 1. Given and explanation

Step 2. Finding the value of first variable by substitution.

Step 3. Finding the value of other variable

Step 4. Check the solution.

One App. One Place for Learning.

Most popular questions from this chapter

Recommended explanations on Math Textbooks

Discrete Mathematics

Logic and Functions

Theoretical and Mathematical Physics

Applied Mathematics

Probability and Statistics

Mechanics Maths

Study anywhere. Anytime. Across all devices.

The sum of two number is $15$ . One number is $3$ less than the other. Find the numbers.