Answer:
Height of boy = 140 cm
Height of sister = 70 cm
Height of father = 170 cm
Step-by-step explanation:
Given that:
Combined height = 3.8 meters = 3.8*100 = 380 cm
Let,
b be the height of boy
s be the height of sister
f be the height of father
According to given statement;
b + s + f = 380 Eqn 1
b = 2s Eqn 2
b = f - 30 Eqn 3
Putting b=2s in Eqn 3
2s = f - 30
[tex]s=\frac{f-30}{2}[/tex]
Putting these values in Eqn 1
[tex]f-30+\frac{f-30}{2}+f=380\\\frac{2f-60+f-30+2f}{2} = 380 \\\\5f - 90 = 760 \\5f = 760+90 \\5f = 850[/tex]
Dividing both sides by 5
[tex]\frac{5f}{5}=\frac{850}{5}\\f=170[/tex]
Putting f=170 in Eqn 3
b = 170 - 30
b = 140
Putting f=170 in Eqn 2
140 = 2s
s = 70
Hence,
Height of boy = 140 cm
Height of sister = 70 cm
Height of father = 170 cm
