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 <<<<<
Answer:
Step-by-step explanation:
(x-3)² - 7 = (5-3)²-7
= 2²-7
= 4 - 7
= -3
Answer:
See below in bold.
Step-by-step explanation:
The triangular piece of cloth is a right triangle because 41^2 = 40^2 + 9^2 (By the Pythagoras theorem).
So the area of one piece = 1/2 * 9 * 40 cm^2.
The total amount of cloth required for one umbrella = 10 * 1/2 * 9 * 40
= 1800 cm^2.
The total cost = 1800 * 0.25 = Rs 450.
Answer:
x-intercept=(-1,0) y-intercept =(0,-3)
Step-by-step explanation:
Answer:
Sarah is paid $20 an hour at her new job. She wishes to graph her total pay y, as a function of the number of hours, x. She wants to be sure her graph shows her pay for 10 and 20 hours of work.
a. What is a good scale to use for the x-axis? Explain your reasoning.
b. What is a good interval to use for the y-axis? Explain your r
Step-by-step explanation:
