Answer:
20ln(3)
Step-by-step explanation:
Put 15 for A and solve for t.
15 = 45e^(-.05t)
15/45 = 1/3 = e^(-.05t) . . . . divide by 45
ln(1/3) = -.05t . . . . . . . . . . . take natural logs
20ln(3) = t . . . . . . . . . . . . . . multiply by 20, simplify
It will take 20·ln(3) years for the area to decrease to 15 km^2.
Answer:
448
Step-by-step explanation:
This is a proportion question. Keep the heights on one side of the proportion and the shadow length on the other.
height ratio shadow ratio
40 cm / x = 25 / 280 Cross multiply
25x = 40 * 280 Combine
25x = 11200 Divide by 25
x = 11200/25
x = 448 cm
The height of the corn plant is 448 cm
Answer:
21
Step-by-step explanation:
average 9 pounds per three weeks
divide 9 in 3 three weeks
3 pounds per week
7 times 3 is 21
Answer: 130 ft
Step-by-step explanation:
a^2 + b^2 = c^2
Where a and b are the legs that form the right angle and c is the hypotenuse (the side directly opposite of the right angle)
50^2 + 120^2 = c ^2
2,500 + 14,400 = c^2
16,900 = c^2
Take the square root of 16,900 to get c.
C = 130
Hypotenuse length is 130