2010-12-0315:121.Take 200 kilometers of water into the city. This task was handed over to two construction teams, A and B, with a construction period of 50 days. After 30 days of cooperation between the two teams, Team B had to leave 655 because of other tasks. Q: How many kilometers did Team A and Team B originally plan to build?

Solution: Let's assume that the original speeds of Party A and Party B are A km and B km per day respectively.

According to the meaning of the question

(a+b)×50=200( 1)

10×(a+0.6)+40a+30b+ 10×(b+0.4)= 200(2)

simplify

a+b=4(3)

a+0.6+4a+3b+b+0.4=20

5a+4b= 19(4)

(4)-(3)×4

A =19-4× 4 = 3km.

B = 4-3 = 1 km

A repairs 3 kilometers every day, and B repairs 1 kilometer every day.

A It was originally planned to build 3× 50 = 150km.

B 1× 50 = 50km as originally planned.

2. Xiaohua bought four mechanical pencil and two pens, and paid 14 yuan; Xiaolan bought the same 1 mechanical pencil and two pens, and paid 1 1 yuan. Find the unit price of mechanical pencil and pen.

Solution: Suppose mechanical pencil has a pen with X yuan and a pen with Y yuan.

4X+2Y= 14

X+2Y= 1 1

The solution is X= 1.

Y=5

In mechanical pencil, the unit price is 1 yuan.

Pen unit price 5 yuan