Solve a math problem Solve an equation, urgently find a math problem, and solve it with an equation

1) Set the speed of the water flow to be x m min

80/(10-x)=(100-80)/x

x=2m/min

2)80/(10-2)=10min

After setting a U-turn, it takes x min to chase the hat

100+2x=(10+2)x

x=10min

It takes a total of 10+10=20min

Solution: (1) Let the water flow velocity be x.

80 10-x=(100-80) x, solution: x=22) set the time of the U-turn back to defraud the hat is y, then there is.

10+2)y-(80+20)=2y, and the total elapsed time of y=10 is y+20 x=20

A: The total elapsed time is 20 minutes.

Let the water velocity be v0, the total time t to get the hat back, and the speed of rowing is v1=10m min, and the system of equations is listed.

v1 multiplied by t1=s

v0 multiplied by t1+s=s1

Known s=80, s1=100

v0=,t1=8min

S total -s cap = 100

s cap = v0t2

Total t = T1 + T2

s total = (v0 + v1) multiplied by t2

Calculate t2 = 10 min

t total = 18 min

See if it's the answer you want, here's my answer.

Let the velocity of the water flow be v.

80 10-v = 20 v (using cross multiplication, note: here is the fraction line) 80 v = 200-20 v

100v=200v=2

Let the top be long x and the root long y when it is broken for the first time, and form a right triangle after folding, according to the Pythagorean theorem

x^2=20^2+y^2

x+5) 2=(20+10) 2+(y-5) 22 minus 1 has x+y=50dm

That is, the height of the rod is 50dm

1.Don't know what you're asking for, don't know how to list.

2.Let each color TV be originally ** x yuan, and the equation can be listed according to the known conditionsNote: Illegal income is the price after the increase - the **x (1+40%) it should be sold

x=4503.Let the cost of the goods be x, and press y**.

y=[x(1+10%)]/[x(1+25%)]y=

y=4.If the number of days for team A to complete is x days, then the number of days for B is 2x days.

If done by A alone, x=20+20 2 x=30 if done by B alone, 2x=60

Team A's work cost = 1000 * 30 = 30000

Team B's work cost = 550 * 60 = 33,000

Therefore, the company should choose Team A and pay 30,000 yuan.

Let the first break to the ground be x, and the length of the break is y

x 2 + 20 2 = y 2

x-5) 2+(20+10) 2=(y+5) 2 gives x+y=50

So the height is 50dm

Set the first break point from the ground xdm

x+√x²+20²=（x+5）+√x-5）²+20+10）²