40+0.5X= 100

X= 120

A: Omit.

2. Solution: Suppose that * * * needs X Jin of wheat to be ground into flour.

X( 1-25%)=625

X≈833

A: Omit.

3. The annual output value is:150000+1.5×1000/100× 250 =153750 =153750 yuan.

I hope you are satisfied. Please ask me again if you don't understand.