Primary school math problems, come and help me solve them, thank you!

1 5 of the number of hectares of grain planted is equal to 1 2 of the number of hectares of cotton, then the number of hectares of grain planted: 5:2 of the hectares of cotton

1 4 of the hectares of cotton planted is 1 2 of the hectares of oilseeds, then the hectares of cotton planted: 4:2 2:1

Grain: Cotton: Oilseeds 5:2:1

So: grain 1200*5 (5+2+1)=750 hectares.

Cotton 1200*2 (5+2+1)=300 hectares.

Oilseed = 1200*1 (5+2+1)=150 hectares.

1 5 hectares of grain is equal to 1 2 hectares of cotton

Grain: Cotton (1 2):(1 5)=5:

2 1 4 of the hectares of cotton planted is 1 2 of the number of hectares of oilseeds, so cotton: oilseeds (1 2):(1 4) 2:

1 So Grain: Cotton: Oilseeds 5:

2:1 grain 1200*5 (5+2+1) 750

Cotton 750*2 5 300

Oil 300 2 150

Let grain, cotton, and oil be x, y, and z respectively

Rule. 1 5 of the hectares of grain is equal to 1 2x:y (1 2):(1 5) = 5:2 of the hectares of cotton

1 4 of the hectares of cotton planted is 1 2 of the hectares of oilseeds, so y:z (1 2):(1 4) 2:1, so x:y:z 5:2:1

Grain 1200*5 (5+2+1) 750

Cotton 750*2 5 300

Oil 300 2 150

Let grain, cotton, and oil be x, y, and z, respectively, and x 5=y 2, y 4=1 z, and x+y+z=1200

700 for grain, 300 for cotton, and 150 for oil

Grain 750, cotton 300

Oilseeds 150 set grain x cotton y oilseeds z

Using the equation 1 5x=1 2y, we get y=2 5x....Equation 11 4y=1 2z gives z=1 5x....The equation 2x+y+z=1200 is brought into the equation to get the conclusion.

The number of hectares of grain planted is x

Cotton is y and oil is z

1/5x=1/2y

1/4y=1/2z

x+y+z=1200

Answer. x=5/2y z=1/2y

y=300 z=150 x=750

Let grain be x, cotton y, and oil z

x+y+z=1200

1/5x=1/2y

1/4y=1/2z

Solve the equation to get:

x=750y=300

z=150

There are 1 6 fewer boys than girls, and the ratio of boys to girls is [5:6].

Solution: The total amount of work is 1, then A's work efficiency is three-thirds, and B's efficiency is two-thirds.

The formula can be calculated from the meaning of the question: (1-25%) divided by (one-third + one-half), (one-third + one-half) is the total amount of work they do in an hour, subtract the work done by A by unit, and the rest is the work of two people, so that the working time = total work divided by work efficiency and.