The perimeter of the original rectangle is:
P = 2w + 2l = 70
The area of the original rectangle is:
A = w * l = 250
Then, by modifying the length of its sides we have:
Perimeter:
P '= 2 (2w) +2 (2l)
Rewriting:
P '= 2 (2w + 2l)
P '= 2P
P '= 2 (70)
P '= 140
Area:
A '= (2w) * (2l)
Rewriting:
A '= (2) * (2) (w) * (l)
A '= 4 * w * l
A '= 4 * A
A '= 4 * 250
A '= 1000
Answer:
the new area and the new perimeter are:
P '= 140
A '= 1000
Answer:
The cross multiplication would be 10(350) = 22(x).
Step-by-step explanation:
We would first convert meters to centimeters. There are 100 cm in a meter; this means 3.5 m = 3.5(100) = 350 cm.
The ratio of the height to base of the model is 10/22. The ratio of the playhouse would then be x/350. This gives us
10/22 = x/350
Cross multiplying, we would have 10(350) = 22(x).
Answer:
21
Step-by-step explanation:
S = d/t
st = d
t = d/s
The time going is t1.
The time returning is t2.
The total time is 4 hours, so we have t1 + t2 = 4
The speed of the current is c.
The speed going is 9 + c.
The speed returning is 9 - c.
t1 = 16/(9 + c)
t2 = 16/(9 - c)
t1 + t2 = 16/(9 + c) + 16/(9 - c)
4 = 16/(9 - c) + 16/(9 + c)
1 = 4/(9 - c) + 4/(9 + c)
(9 + c)(9 - c) = 4(9 - c) + 4(9 + c)
81 - c^2 = 36 - 4c + 36 + 4c
81 - c^2 = 72
c^2 = 9
c^2 - 9 = 0
(c + 3)(c - 3) = 0
c + 3 = 0 or c - 3 = 0
c = -3 or c = 3
We discard the negative answer, and we get c = 3.
The speed of the current is 3 mph.
