Answer:
Mel's height is 159cm, her brother's height is 177cm and their grandma's height is 166cm.
Step-by-step explanation:
Let the grandma's height be g cm.
Mel's height= (g -7) cm
Brother's height= (g +11) cm
Total height
= Mel's height +brother's height +grandma's height
= g -7 +g +11 +g
= (3g +4) cm
Given that their total heights is 502 cm,
(3g +4) cm= 502 cm
3g +4= 502
3g= 502 -4 (-4 on both sides)
3g= 498
g= 166 (÷3 on both sides)
To find their heights, substitute g= 166 back into the expressions.
Grandma's height= 166cm
Mel's height
= 166 -7
= 159cm
Brother's height
= 166 +11
= 177cm
