Below is an instruction that describes a task. Write a response that appropriately completes the request in Spanish. Please answer in Spanish.

### Instruction:
 George donated half his monthly income to charity and spent $20 from the other half on groceries. If he now has $100 left, how much was his monthly income?


### Response:
 Supongamos que su ingreso mensual es x.
La mitad de su ingreso mensual = <<x/2>>x/2
La otra mitad de su ingreso mensual = <<x/2>>x/2 - 20
100 = <<x/2>>x/2 - 20
100 + 20 = <<x/2>>x/2
120 = <<x/2>>x/2
240 = x
Su ingreso mensual es de $240.