Jhon and jane purchased total 5 cookies.
Linear equation in one variable:
An equation which is expressed in the form of ax +b = 0, where a and b are two integers, and x is a variable and has only one solution is called linear equation in one variable.
Unitary method:
The method which is used for solving a problem by first finding the value of a single unit, and then finding the necessary value by multiplying the single unit value is called unitary method.
According to the given question
Jane bought x cookies. Price of each cookies is $3.
⇒ Total price of cookies = $3 × x = 3x
John also bought x cookies. Price of each cookies is $1.
And a small cake for $10.
⇒ Total price of cookies and cake = $10 + x($1) = (10 + x)$
Since, John and Jane both spent the same amount of money
⇒ (10 + x) = 3x
⇒ 10 + x = 3x
⇒ 10 = 3x -x
⇒ 10 = 2x
⇒ x = 10/2
⇒ x = 5
Hence, Jhon and jane purchased total 5 cookies. And, 10 + x = 3x a linear equation in one variable which represent the number of cookies they purchased.
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