1, Master Zhang processed a batch of parts, and the ratio of the number completed on the first day to the total number of parts was 1: 3. If 15 parts are processed again, half of the parts are completed. How many parts are there in this batch?

explain

The first day is 1/3 of the total, so the * * * part is:

15/( 1/2- 1/3) = 90.

2.5438 June+February 2009, yang shen and Liu Qian drove from A and B to perform somewhere at the same time, and met two hours later. After meeting, they moved on. When Xiao Shenyang's car arrives at B, Liu Qian's car is 60 kilometers away from A. Knowing the speed ratio of the two cars is 3: 2, we can find out the speed of Xiao Shenyang and Liu Qian.

explain

Let Shenyang's speed be 3x and Liu's speed be 2x, so the whole journey is 2*(2x+3x)= 10x.

According to the isochronous sequence equation:

10x/(3x)=( 10x-60)/(2x)

10/3=( 10x-60)/2x

3( 10x-60)= 10*2x

30x- 180=20x

x= 18

Answer: The speed of Xiao Shenyang is 18*3=54 km/h, and that of Liu is18 * 2 = 36 km/h.