Math Problem A What is the chronological age of B? See additional notes .

Solution 1: According to the question: B-(A-B)=4

A + (A-B) = 61

Solution: A = 42 B = 23

Solution 2: Set A to be x years old and B to be y years old.

then y-(x-y)=4

x+（x-y）=61

x=42 y=23

Solution 3: Set: A x years old, B x x years old.

From condition 1: B is 4 years old before n, i.e. (x-n)-n=4 by condition 2: A is 61 years old after n, i.e., x+n=61

Solution: x=42

n=19 So A is 42 years old and B is 23 years old.

One answer is explained by the brothers, which is very correct and admired.

The other is that if the two are not in the same plane, they may not be.

Oh, it's a bit far-fetched, don't laugh.

Adjust the atmosphere.

Set: A x years old, B x x - n years old.

From condition 1: B is 4 years old before n, i.e. (x-n)-n=4 by condition 2: A is 61 years old after n, i.e., x+n=61

Solution: x=42

n=19 So A is 42 years old and B is 23 years old.

Oops, I'm so tired, it's finally figured out! I agree with the answer above.

Let A's age be x years old, then B's age is (x+5) years and C's age is (2x+5) years.

x+x+5+2x+5=46

x=9 i.e., A's age is 9 years old.

Elementary school algorithm: (46 2-5) 2=9

According to the meaning of the equation: A + B = C.

A + B + C = 46

The sum of the ages of A, B and C is equal to 46 years old, and the sum of the ages of A and B is equal to the age of C.

So C's age is 46 years old 2=23 years old.

The sum of the ages of A and B is equal to 23 years old.

A is 5 years younger than B, and A's age is: (23-5) 2=9 years.

A: A's age is 9 years old;

According to the title, you can know:

A + B = C.

A + B + C = 46

So there is 2C = 46, C = 46 2 = 23

A B = 23, and A is 5 years younger than B, so A = (23-5) 2 = 9 Answer: A is 9 years old.

The sum of the ages of A and B is equal to the age of C, and the sum of the ages of A, B and C is equal to 46, so that we can know that C's age is 23 years old, that is, the sum of the ages of A and B is also 23 years old, and A is five years younger than B, so that A's age is nine years old.

A is 9 years old. A + B = C, A + B + C = 46, C = 46 2 = 23 (years), A = (23-5) 2 = 9 (years), so A is 9 years old.

A + B = C, A + B + C = 46

A + B = 46 2 = 23

A + 5 = B.

A = (23-5) 2 = 9

A: A's age is 9 years old;

A10B = C.

A, ten, b, ten, C = 46

2C=46 C=46 2=23

A, ten, B, = 23

A105=B.

2 A 10 5 = 23

A = (23-5) 2 = 9 (years).

A is 9 years old.

Let A be the age of , then B is ( +5) years old, let C be y years old, from the title y=2x+5, 2x+2x+5=46, so x=14

46 2-5) 2=9 years old.

46 2 = 23, is the age of C.

23-5, that is, except for the eldest 5 years old, after that, the rest are separated, which is the age of A.

A is 5 years younger than B, indicating that B = A + 5

The sum of the ages of A and B = 2 A + 5 = C.

The sum of the ages of A, B and C = 2, C = 2, A + 5 + C = 46

According to the title.

9 years old. A: A is 9 years old.

A is 9 years old, B is 14 years old, and C is 23 years old.

Let A's current age be x, and A's current age is y, then it can be seen from the title that A's age is greater than B's, and the difference between them is (x-y), when A is B's current age, B is 10 years old.

In other words, the age of A and B has become younger.

A and B are now (x-y) years younger than before.

Then there is 10=y-(x-y).

When B is A's current age, A is 25 years old, which means that they are all older, older than the original (x-y).

then there is 25=x+(x-y).

The two-way solution is solved.

x=20y=15

So A is now 20 years old and B is now 15 years old.

Draw a line diagram to see that the age difference between A and B remains unchanged, is: (15-10) 3=5 years A: 25-5=20 years old.

B: 20-5 = 15 years old.

Explain that now A is x years old and B is y years old, and A is older than B, and the age difference is x-y.

The first sentence means that when A is y, B is 10.

The known age difference is y-10.

Then x-y = y-10, and the shift gives x+10=2y

The second sentence is easy to get an age difference of 25-x

Then x-y=25-x, and the shift yields 2x-25=y.

Solving the binary equation yields x=20, y=15.

A is 20 years old and B is 15 years old.

Assuming that A is x, B is y, and the age difference is a=x-y, then y-a=10

x+a=25

Let B x, then A 50-x

A is 50-x-x larger than B

When A is the size of B, A is x, and B is x-(50-x-x).

x/2=x-（50-x-x)

x=20

Let A be aged x this year, then B will be (50-x) this year.

If the age of A before n years is twice the age of B, then the age of A before n years is (50-x) and the age of B is (50-x) 2

A system of column equations. 50-x)+n=x

n=(50-x)

Solution: x=30, n=10

This year, A is 30 years old and B is not 20 years old.

Let A's age be x years and B's age be (50-x) years.

x-（50-x）=1/2（50-x）

2x-50=25-x/2

x=30so: 50-x=20

A: A's age is 30 years old and B's age is 20 years old.

He is 42 years old and B is 56 years old.

The age difference between the two remains the same, and the difference is equal to x. It is easy to determine the age of B from the title. When X years ago, B's age (minus x years) is A's current age, A's age should also be reduced by one x to half of B's current age, so that B's age is 4x and A's age is 3x, a total of 7x=98, which gives x=14.

He is 42 years old and B is 56 years old.

Method 1:

Analysis: From "A's age is half of B's age, B is exactly A's current age", we know: A--B=B2--A, pushout: 2A=3B2;The ratio of A to B is 3:4.

A: 98x3 7 = 42 years old.

B: 98x4 7 = 56 years old.

Method 2: Let the ages of A and B be x and y years old.

So the column equation gets:

x+y=98

y-(x-y 2)=x (when A is half the age of B, 2 years from now) gets: x=42, y=56

Let A be aged x this year, then B will be (50-x) this year.

If the age of A before n years is twice the age of B, then the age of A before n years is (50-x) and the age of B is (50-x) 2

A system of column equations. (50-x)+n=x

n=(50-x)

Solution: x=30, n=10

This year, A is 30 years old and B is not 20 years old.

Let A's age be x, B's age be 50-x, and the difference between the ages of A and B is 2x-50 and A is greater than B (50-x)=2(2x-50).

x=30

Solution: Let A be x years old now, then B is now (63-x) years old, and when A is 1 2 of B's current Zheng Shiyan age, that is: 1 2 (63-x).

B is x years old, so.

x-1/2（63-x）＝（63-x）-x

So x 27

B's age is 63-27-36

The silver shouted was compared to B to A.

Big 36-27 9

That is: B is 9 years older than A and returns.

It should be noted in this question that no matter how old the two people are, the age difference between the two will not change, which is the key to this question. According to the given conditions, we assume that A's age is x, and the age difference between A and B is a (A can be negative), then B's age is x+a, and the sum of their ages is (1）2x+a=98

When A's age is half of B's age, we can express it as (x+a 2), B's age is equal to A's current actual age, which is x, because the age difference is not equal, we get the equation (2）x-（x+a/2）=a

We can calculate x=3a, substituting the equation (1.But Liang Shu obtained a = 14, and the comprehensive calculation resulted that A's age was 42 years old and B's age was 56 years old.

Method 2: Let the ages of A and B be x and y years old.

So the column equation gets:

x+y=98

y-(x-y/2)=x

When A is half the age of B, it is 2 years from now x-y).

Solution: x=42, y=56

The age of A and B is x and y years old.

So the column equation gets:

x+y=98

y-(x-y/2)=x

When the age of A Hail Qing is half a year of B Yi Liang and half a day, it is 2 years away from the present) to solve: x=42, y=56

Set A to be x years old and B y years old.

x+y=45

x-y=27

x=36 y=9

The second. x+y=45

y-x=27

x=9 y=36

Answer: Case 1 A is 36 years old B 9 years old, Case 2 A is 9 years old B is 36 years old.

Let A and B be x and y years respectively.

A system of equations can be listed.

x+y=45...1)

x- y=27...2)

1)-(2) can give 2y=18, and get y=9x=45-y=36

So A is 36 years old and B is 9 years old.

Let A be x years old and B be y years old.

x+y=45，x-y=27

The solution is x=36 and y=9

So A is 36 years old and B is 9 years old.

Older: (45+27) 2 36 years old.

Lesser: 45-36 9 years old.