Answer:
b
Step-by-step explanation:
United States
3.30404742 x 10^8 scientific notation
330,404,742 standard
Cincinnati
3.02605 x 10^5 scientific notation
302,605 standard
China
1.394015977 x 10^9 scientific notation
1,394,015,977 standard
Short Answer: 18 minutes
Remark
The answer to this problem is less than the smallest time of the two people working together. that fact lets out C and D (38 minutes and 75 minutes). Now you have to choose 15 minutes and 18 minutes. There's a method. No guessing needed.
Givens
Let the time for Sophie = S
Let the time for Simon = M
Let the job to completion = 1
S = 45 minutes
M = 30 minutes
Step One
Convert minutes to hours.
45 minutes = 45 / 60 = 3/4 hour = 0.75 hour
30 minutes = 30 / 60 = 1/2 hour = 0.50 hour
Step Two
Set up the Equation
The formula is a form of job / hour.
Let the time = t that they both have to work
job = 1 in these problems.
1/S + 1/M = 1/t
1/0.75 + 1/0.5 = 1/t
Solve
1 ÷ 0.75 = 1.33333
1 ÷ 0.5 = 2
1.3333 + 2 = 3.33333
3.3333 = 1 / t Multlply both sides by t
3.3333*t = 1
t = 1 / 3.333333333
t = 0.3 of an hour
1 hour = 60 minutes
0.3 hours = x Cross Multiply
x = 60 * 0.3
x = 18 minutes
Answer working together it took them 18 minutes <<<<<
The tree is 25 feet tall. Given the height of the stick and the shadow it cast, the angle formed by the sun and the stick's height can be obtained by taking the Inverse Tangent of 3/5. This is equal to 30.93. This angle is equal to the angle formed by the sun and the tree's height. Using the tangent formula, Tan (30.93)=tree's shadow (15 ft)/ height of the tree, giving the answer 25 feet.
Answer:
2i x 1.50b
Step-by-step explanation:
