a+b=38

a/2=b-2

a=2b-4

2b-4+b=38

B = 14m

A=24 meters

Second, suppose a * * * has x boxes, then 25x+40 = 30x (x-30), and x= 188 is obtained.

3. Let A loan be X, then B is 35-x, the equation is: 6%×x+7%×(35-x)=2.25, and the solution is x=20, then A is 200,000, and B is 1.5 million.

4. The two trains depart from two opposite places at the same time, with a distance of 9 10km, and meet after 10 hour: the sum of the speeds of the two trains is 910/0 = 91km/h.

The second train leaves 4 hours and 20 minutes later than the first train, so they meet 8 hours after the second train leaves, which means that the distance traveled by the first train in 4 hours and 20 minutes is the same as the total distance traveled by two trains from two places at the same time. So 9 1×2 is the total distance traveled by the first train for four and a third hours, so the speed of the first train is 9 1×2÷( 13/3)= 42 km/h, and the second train is 9 1-42 = 49.