Answer:
21 windows
Step-by-step explanation:
collen family plans to paint the windows of their house. her father will paint twice as many windows as her mother, and collen and her 2 brothers will paint an equal number of the rest of the windows. Colleen decided to do her own share and her mother's share and paints 7 window, which is one less than her father's share. how many windows are in their house?
Answer: Let the number of window Collen father would paint be a while that of her mother be b. Since her father will paint twice as many window as her mother, therefore the number of windows painted by the father a = 2b
Let the number of windows that would be needed to be painted each by Colleen and her 2 brothers be c because they would paint the equal number of windows.
The total number of windows to be painted = 2b + b + c + c + c = 3b + 3c = 3(b + c).
Collen painted 7 windows as her mother and her own share which is one less than the fathers share. Therefore b + c = 7.
Also the fathers share a = 2b = 7 + 1 = 8 windows. Therefore b = 4 which is the mother share
Therefore the total number of windows = 3(b + c) = 3(7) = 21 windows
3b + 3c = 21
3(4) + 3c = 21
12 + 3c = 21
3c = 21 - 12
3c = 9
c = 3 which is collen and her brothers share
