The sum of the ages of a father and a son is 56. four yrs ago the father was 3 times as old as the son. find the current age of them both.

I think the current age of the child is 16 and the father is 40. That would mean 4 years ago the father was 36 and the child was 12. This makes the father 3 times as old as his son four years ago.

let x is father and y is son

x+y=56

x=56-y

x=3y

(56-y)-4=5(3y-4)

52-y=15y-20

52+20=15y+y

72=16y

y=72/16

y=4year with 6month

y=4.5+4=8.5yr "current age"

x=3(4.5)

=13.5 year

×=13.5+4

x=17.5 yr "current age"

1.4

2.3

step-by-step explanation:

the formula for the constant of variation is

y= kx

divide each side by x

y/x =kx/x

y/x =k

we know a and y

1.   y/x = k

4/1 =4

check the other values to make sure they are the same

8/2 = 4   12/3 =4   and 16/4 =4  

the constant of variation is 4

2.   y/x = k

3/1 =3

check the other values to make sure they are the same

6/2 = 3   9/3 =3   and 12/4 =3  

the constant of variation is 3

13

step-by-step explanation:

169-1=168

168-3=165

165-5=160

160-7=153

153-9=144

144-11=133

133-13=120

120-15=105

105-17=88

88-19=69

69-21=48

48-23=25

25-25=0

since it took 13times to completely subtract it hence its square root is 13