Algebra in Everyday Life

We use algebra quite frequently in our everyday lives, and without even realizing it! We not only use algebra, we actually need algebra, to solve most of our problems that involves calculations.

Examples of using algebra in everyday life


Here are some simple examples that demonstrate the relevance of algebra in the real world.


Example 1:
You purchased 10 items from a shopping plaza, and now you need plastic bags to carry them home. If each bag can hold only 3 items, how many plastic bags you will need to accommodate 10 items?
  `(text(10 items))/(text (3 items/bag))` = `3.33` bags ≈ `4 bags `

Explanation :

The figure below illustrates the problem:
The different shapes inside the bags denote different items purchased. The number depicts the item number.

Algebra in Daily usage - Shopping Bag

We use simple algebraic formula `x/y` to calculate the number of bags.


x = Number of items purchased = 10

y = Capacity of 1 bag = 3

Hence,


`10/3` = `3.33` bags ≈ `4` bags

So,we need 4 shopping bags to put 10 items.

Example 2:
You have to buy two dozen eggs priced at $10, three breads (each bread is $5), and five bottles of juice (each bottle is $8). How much money you will need to take to the grocery store?
 $65

Explanation :

The figure below shows the three items in different shapes and colors.

This will help your mind to calculate faster.

Algebra in Daily Life Exmaple with shopping

We will use algebra to solve the problem easily and quickly.


The prices are


a = Price of two dozen eggs = $10

b = Price of one bread = $5

c = Price of one bottle of juice= $8


=> Money needed = a + 3b + 5c

=> Money needed = $10 + 3($5) + 5($8) = $10 + $15 + $40 = $65

Example 3:
You need to fill the gas tank but you have only $15 in your pocket. If the price of the gas is $3 a gallon, how many gallons can you buy?
 `5 ` gallons

Explanation :

In the below diagram, each block represents $1, and each row is a bundle of $3, which is used to buy 1 gallon of gas.

Algebra in Daily Life example gas refill

We use simple algebraic formula,`x/y` to calculate the total gallons that can be bought.


x = Money in your pocket= $15

y = Price of 1 gallon of gas= $3

Hence,


`($15)/($3)` = 5 gallon


So, with $15 we can buy 5 gallons of gas.


Word problems


Life's many problems are disguised in the form of math equations, and if we know the math, it's fairly simple to solve those problems.


Example 1:
  71, 72 and 73

Explanation :

1.  Understand the problem

The task is to find three consecutive numbers whose total is 213.


2.  Write the variable

Let "`x`" represent the first number

So, `x` = first number

`x+1` = second number

`x+2`= third number


3.  Write the equation

When you add up all the numbers, you are supposed to get 216

`x + (x + 1) + (x + 2 )`= 216

`3x + 3 `= 216


4.  Solve the equation

Subtract 3 from both sides

`3x + 3 - 3 `= 216 - 3

`3x ` = 213

Divide each side by 3

`(3x) / 3 `= 213 ÷ 3

`x = 71`


5.  Check your answer

First number + Second number + Third number = 216

`x + (x + 1 )+ (x + 2)`

71 + (71 + 1) + (71 + 2)

71 + 72 + 73 = 216

So the three numbers whose sum is 216 are 71, 72 and 73

Example 2:
 $13

Explanation :

1.  Understand the problem

A group of 5 boys goes to the theatre. The cost of ticket and popcorn is $55 and $10 respectively. What is cost per person?


2.  Write the variable

Let’s say, `x` = cost of ticket/person and `y` = cost of popcorn/person


3.  Write the equation

If 5 tickets cost $55, then cost of one ticket is,

`5x` = 55

`x ` = `55 / 5`

If 5 bags of popcorn cost $25, then the cost of each bag is,

`5y ` = 10

`y ` = `10 / 5`

Total cost of the movie (ticket + popcorn) per person = `x + y `


4.  Solve the equation

Cost of ticket/person

`x` = `55 / 5`

`x` = $11

Cost of popcorn/person

`y ` = `10 / 5`

`y ` = $2


5.  Check your answer

Cost of ticket/person + Cost of popcorn/person = Total cost

11 + 2 = 13


If we add up 13 five times (since there are 5 boys), the result is,

13 + 13 + 13 + 13 + 13 = 65

$65 is the total cost.

Example 3:
 The length is 6 cm and the width is 12 cm

Explanation :

1.  Understand the problem

The area of a rectangle is 72 cm. The width is twice its length. What is the length and width of the rectangle?


2.  Write the variable

Let "`x`" be the length and "`2x`" be the width


3.  Write the equation

Length `×` Width = Area

`x ` x `(2x)` = `2x^2 `= Area


4.  Solve the equation

`2x^2` = Area

`2x^2` = 72

`x^2` = `72 / 2`

`x^2` = 36

`x` = 6

`x ` = Length

So, the length is 6 cm

The width is twice its length

`2x` = 2 x 6 = 12

So, the width is 12 cm


5.  Check your answer

The length is 6 cm and width is 12 cm

The perimeter i.e. the distance around the edges is the sum of lengths and widths. Since rectangle has two lengths and two breadths hence the equation is,


2 x (length + width)

2 x (6 + 12) = 2 x 18 = 36 cm