Xiao Qiang's monthly housework time does not exceed 20 hours, and 2.5 yuan is rewarded every hour; If Xiao Qiang spends more than 20 hours doing housework every month, then the reward for 20 hours is 2.5 yuan per hour, and the reward for more than 20 hours is 4 yuan per hour. (The answer is not unique)
(2)y=2.5x+ 150
(3) When x≥20, the functional relationship between y and x is y=4x+ 120.
From the meaning of the question, 4x+ 120=250 gives x=32.5.
A: When Xiao Qiang does 32.5 hours of housework in April, the available cost in May is 250 yuan. Hope to adopt ~ Happy New Year's Day!