80(2 1+x)= 60(2 1-x)

63+3 times = 84-4 times

7x=2 1

x=3

Solution: Assuming that X pieces are processed every hour, it is 2.5X pieces after improvement.

1500/X- 1500/2.5X = 18 1500 * 2.5- 1500 = 18 * 2.5 xx = 502.5 X = 2.5X 50 = 125

Suppose the speed of bicycle is X, then the speed of bus is 3X.

According to the meaning of the question, we can get 25÷X=25÷(3X)+2.

X = 25/3 = 8.33/h,

3x = 25km km/h.

A: The speed of bicycle is 8.33 km/h, and that of bus is 25 km/h. ..

Solution: Suppose I read Page A every day.

140/a+140/21= 7× 2a = 210/1=19 and1/.

Read 20 pages

Solution: Let the original speed be x, the original required time be 90/X, and the actual required time be 1+(90-X* 1)/2X.

Equation 90/x-40/60-20/60 =1+(90-x *1)/2x is derived from the time difference.

90/x- 1 = 1+90/2x- 1/245/x = 3/2x = 30k m/h

The original speed of motorcycle is 30 km/h.

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