human
Kenneth spent 10% of this earnings this week on a new joystick. If he is left with $405, how much were his earnings?
assistant
How much is Kenneth left with? ** Since Kenneth spent 10%, then he is left with 100% - 10% = 90% of his earnings.
How much was his earnings? ** Since 90% of his earnings is worth $405, then 1% of his earnings is $405/90 = $<<405/90=4.50>>4.50.
How much were his earnings? ** Hence, Kenneth's earnings is $4.50 x 100 = $<<450=450>>450.
#### 450