Roberto should work for 6.25 hours to earn the money he needs, solved using linear equations in one variable.
What are linear equations in one variable?
Linear equations in one variable are a relation between two algebraic expressions, involving not more than one variable.
The expressions are a combination of terms and terms are combinations of variables and constants. These terms are separated by mathematical operations.
How to solve the question?
In the question, we are informed that Roberto wants to buy a $40 gift for his father. He finished one odd job in 4 hours at $3.75 an hour. He is now working at a job that pays $4.00 an hour.
We are asked how many hours he needs to work to earn the money he needs.
First, we calculate how much he earned from working in the first place.
He worked there for 4 hours at $3.75 an hour.
Therefore, his total income = Time * Income per unit time = $ (4 * 3.75) = $ 15.00.
Now, we calculate how much more money he needs.
More money needed = Total money needed - Money already earned,
or, more money needed = $40 - $15 = $25.
Therefore, Roberto works in second place to earn $25.
The rate at which he was working = $4 per hour.
We assume the time he worked for was x hours.
Therefore, his total income = Time * Income per unit time,
or, His total income = $ (x*4) = $4x.
As his total requirement is $25, we equate his earnings to his requirement to get the required linear equation in one variable:
4x = 25.
We find the hours he will work for, by solving this equation, by dividing both sides by 4:
4x/4 = 25/4,
or, x = 6.25.
Therefore, Roberto should work for 6.25 hours to earn the money he needs, solved using linear equations in one variable.
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