Help me do the math, help me do some math

Set to complete x long roads every day.

8x=1500*40%

x = 75 m d (m days).

At this pace, the number of days remaining to complete the remaining project:

1500-1500*40% 75=12 d (day) After the work efficiency is increased by 20%, the length of the road repair completed every day:

75*120%=90 m/d

The number of days required to complete the remaining project at the pace of efficiency improvement:

1500-1500*40% 90=10 d (days), so 2 days earlier than originally planned.

2 days in advance Solution: The original plan was to repair every day: 1500 40% 8=75 (m).

Work remains: [1500 (1-40%)] [75 (1+20%)]=10 (days).

is ahead of the original plan: 1500 75-(10+8)=2 (days).

1500 75 = 20 days.

1500*(1-40%) (75*120%)=10 days.

20-(8+10)=2 days.

2 days ahead of schedule.

8 days to complete 40, then complete 40 8 5 per day The ergonomics are increased by 20, then the current ergonomics is: 5 (1+20%) 6 There is 1 40 60 left

It turned out to be 60 5 12 days.

Now it's going to be 60-6-10 days.

12 10 2 days in advance.

1500*40%=600m completed.

600 8=75 m days plan efficiency.

75*(1+20%)=90 m days after improving efficiency.

1500*(1-40%)900m remaining works.

900 90 = 10 days The number of days required for the remaining work after the efficiency is improved.

900 75=12 days The number of days required for the remaining work in the original plan.

12-10=2 days in advance.

Solution: 1500 40% 8=75 (m-day) (originally planned efficiency) 1500 (1500 40% 8)=1500 75=20 (day) (originally planned to be completed in 20 days).

1500 (1-40%) = 900 (m) (remaining workload) 1500 (1-40%) 75 (1+20%) = 10 (days) (number of days required for the remaining workload).

20-8-10 = 2 (days) (days earlier than originally planned).

Originally planned to be completed per day: 1500 40% 8=75

Actual daily completion: 75 (1+20%)=90

This can be earlier than originally planned: 1500 75-1500 90 = 20-16 and 2/3 = 3 and 1/3

From the second group, we can see that the weight of the square + circle is 11 kg, combined with the first group, the triangle is 12 kg, and the third group is combined to get the circle is 4 kg, so the square is 7 kg. x+y+z=23

2y+2z=23

2x+z=28

24 (3-1) = 12, Xiaohong is 12 years old, and Mom is 36 years old.

According to the inscription, a total of 200-5=195 tons of wheat were transported, and this Yinxun liquid and some Changqiao wheat were transported by five trucks for three days.

Therefore, if x tons are transported per day, then 3*5x=195 will be solved to x=13 tons.

Solution: (Analysis: The graph of this problem is actually a combination of two special right triangles, and due to the small amount of data, it will be difficult to use the direct calculation method, so it is recommended to use the counter-proof method.) The idea is simple and not easy to make mistakes. The process is as follows).

Let this newly built road just tangent to the edge of the park, because the radius of the park is meters, and the distance between the two points ab can be obtained from an isosceles right triangle and a right triangle of 30°60° is: root number 3=<2, so it proves that the distance from point c in the center of the park to the straight line ab is greater than that. The assumption is not true.

To sum up, the road is outside the park.

Walk through the park. Let the CH intersect vertically at AB, and if AB grows longer than the radius of the park, it will pass through the park.

The 60° east-north angle A of place A is 30 degrees, and the angle of B is 45° north of the west of 45° of B.

Right triangle ach, bch.

ah=root3ch; ch=bh

That is, ab = ah + bh = root number 3 ch + ch = 2 root number 3 = ch = >

No, it can be calculated that the perpendicular distance of point C from the AB line is.

Hehe, it seems that I'm counting so many people this time. Not bad.

To add, when doing this kind of problem, first make an auxiliary line on the diagram, and then it will be clear at a glance.

cab30 degrees, abc 45 degrees, acb105 degrees sine theorem ac sin abc=ab sin acbac=

C to AB distance ac*sin cab=

Won't be crossed.

The original number was 10x+1

The new number is 10+x

10x+1-（10+x）=18

x=3, so the original two-digit number is 3*10+1=31

18+1*10+x=10x=1

x=3, the original number is 31, and the new number is 13

1, C 2 = A 2 + B 2, C 2 = 2AB, a = b then the right triangle is an isosceles right triangle, then there is an acute angle of 45 degrees 2, a = 30 degrees, then b = 60 degrees.

a=c*sina=c/2

b=c*sinb=√3c/2

a：b:c=1/2:√3/2:1

a=45 degrees, then b=45 degrees.

a=b=sina=√2c/2

a:b:c=√2/2:√2/2:1