###Human: 40 less than 10 times Diaz's age is 20 more than 10 times Sierra's age. If Sierra is currently 30 years old, how old will Diaz be 20 years from now?, ### Assistant: If Sierra is currently 30 years old, 10 times her age is 30*10 = 300.
Twenty more than 10 times Sierra's age is 300+20 = 320
320 is 40 less than ten times Diaz's age so 10 times Diaz's age is 320+40 = 360
If ten times Diaz's age is 360, Diaz is 360/10 = 36 years old.
Twenty years from now, Diaz will be 20+36 = 56 years old. 
 So the answer is :  56