Question

John has $8 in his bank account when he gets a job. He begins making $80 a day. A student found that

the equation that represents this situation is y = 8x + 80.
What is wrong with the student's equation? Complete the explanation and correct the student's error.

Answer 1

y = 8 + 80x

Explanation:

Given,

The equation is, y = 8x + 80

It is the wrong equation. Because John has $8 in his bank when he gets a job. It means it is fixed. On the other hand, since he begins earning $80 per day. It becomes variable earnings for him. We know that variables (x, y, z) are multiplied by the variable number (If there is no value for variables). Therefore, the equation will be =

As $8 is fixed and $80 is a variable earnings,

y = 8 + 80x

Here, x represents the number of days John will work. If he works for 20 days, the value will be changed for the number of days he earns. The fixed amount will never be changed.