Grandfather

The grandfather is three years older than an grandmother. The average age of the grandmother, the grandfather and their seven grandchildren is 28 years. The grandchildren have a total of 105 years. Calculate how old is grandfather.

Result

o =  75

Solution:


o = m + 3
(m+o+7*v)/(1+1+7) = 28
v = 105/7

m-o = -3
0.111111m+0.111111o+0.777778v = 28
7v = 105

m = 72
o = 75
v = 15

Calculated by our linear equations calculator.







Leave us a comment of example and its solution (i.e. if it is still somewhat unclear...):

Showing 0 comments:
1st comment
Be the first to comment!
avatar




Looking for help with calculating arithmetic mean? Looking for a statistical calculator? Do you have a linear equation or system of equations and looking for its solution? Or do you have quadratic equation?

Next similar examples:

  1. Schools
    bulb2_2 Three schools are attended by 678 pupils. To the first attend 21 students more and to the third 108 fewer students than to second school. How many students attend the schools?
  2. Boxes
    krabice 200 boxes have been straightened in three rows. The first was 13 more than in the second, and in the second was one fifth more than in the third one. How many boxes are in each row?
  3. Ages 2
    time_13 A man's age is 4 times his son's age. After 5 years he will be just twice his son's age, find their ages.
  4. Football season
    ball_f Dalibor and Adam together scored 97 goals in the season. Adam scored 9 goals more than Dalibor. How many goals scored each?
  5. Ball game
    lopta_3 Richard, Denis and Denise together scored 932 goals. Denis scored 4 goals over Denise but Denis scored 24 goals less than Richard. Determine the number of goals for each player.
  6. Antennas
    antenas If you give me two antennas will be same. If you give me again your two antenna I have a 5× so many than you. How many antennas have both mans?
  7. Ravens
    havrany On two trees sitting 17 ravens. If 3 ravens flew from first to second tree and 5 ravens took off from second tree then the first tree has 2 times more ravens than second tree. How many ravens was originally on every tree?
  8. Two numbers
    maxwells-equation We have two numbers. Their sum is 140. One-fifth of the first number is equal to half the second number. Determine those unknown numbers.
  9. Substitution
    eq1_5 solve equations by substitution: x+y= 11 y=5x-25
  10. School year
    boys_girls At the end of the school year has awarded 20% of the 250 children who attend school. Awat got 18% boys and 23% of girls. Determine how many boys and how many girls attend school.
  11. Viju
    chicken_2 viju has 40 chickens and rabbits. If in all there are 90 legs. How many rabbits are there with viju??
  12. Linsys2
    linear_eq_3 Solve two equations with two unknowns: 400x+120y=147.2 350x+200y=144
  13. Equations
    p1110617 Solve following system of equations: 6(x+7)+4(y-5)=12 2(x+y)-3(-2x+4y)=-44
  14. Mushrooms
    huby_2 Eva and Jane collected 114 mushrooms together. Eve found twice as much as Jane. How many mushrooms found each of them?
  15. Two equations
    children_23 Solve equations (use adding and subtracting of linear equations): -4x+11y=5 6x-11y=-5
  16. Linear system
    linear_eq_2 Solve a set of two equations of two unknowns: 1.5x+1.2y=0.6 0.8x-0.2y=2
  17. Mean
    integrales if the mean of the set of data 5, 17, 19, 14, 15, 17, 7, 11, 16, 19, 5, 5, 10, 8, 13, 14, 4, 2, 17, 11, x is -91.74, what is the value of x?