I could be wrong but I got 28. I devided 420 by 15
Well nine times 199 is 1,791but im not sure if thats what its asking
In this problem, we have been given that there is a baby and the weight of the baby is £10 at birth and it is observed that after four years. That means when time is four years, the weight of the baby, That is observed to be 40 lb. And here, considering the weight of the baby to be increasing linearly with respect to the time. In years, we have to express this weight in terms of. So as we are given that the weight is a linear function of time teeth. So in that case this is the way by which we say that y is a linear function of X. And instead of X, let's put T here. And instead of white, let's put W to indicate that weight is a linear function of time. And as we are given that at birth, that is a physical 20 years. The way it is £10. So we substitute T. S. Zero and ws £10 in this equation. So we're going to get 10 equals zero times A. That's zero plus be solving this, we're gonna get Bs 10 and putting this value of weight as 40 lb and the time has four years as well In the same equation, we're going to get 40 equals four A plus B. And we already have determined B. Let's put that here and solving this, we're going to get the value of a coming out to be seven point fight. And now let's put the values of A. And B back into this equation of W. So we get ws eight times t. That's 7.5 times T Plus B. That's 10. So this is the expression, in fact, we can say this is the linear expression for W with respect to time.
The wall area is the product of the room perimeter and the room height:
A₁ = (2*(12.5 ft + 10.5 ft))*(8.0 ft) = 368 ft²
The window and door area together is
A₂ = 2*((4 ft)*(3 ft)) + (7 ft)*(3 ft) = 45 ft²
The area of one roll of wallpaper is
A₃ = (2.5 ft)*(30 ft) = 75 ft²
Then the number of rolls of wallpaper required will be
1.1*(A₁ - A₂)/A₃ ≈ 4.74
5 rolls of wallpaper should be purchased.
_____
As a practical matter, not much of the window and door area can be saved. The rolls are 30 inches wide, but the openings are 36 inches wide. Some will likely have to be cut from two strips. The strips will have to be the full length of the wall, and the amount cut likely cannot be used elsewhere. If the window and door area cannot be salvaged, then likely ceiling(5.4) = 6 rolls will be needed (still allowing 10% for matching and waste).
