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 first option and the third option are correct.
(Although, it's probably way too late now...)
Answer:
Step-by-step explanation:
There’s no equal sign.
Given 2.50x + 3.50y < 30.
Where x represent the number of hamburgers and y represent the number of cheeseburgers.
Now question is to find the maximum value of hamburgers Ben could have sold when he has sold 4 cheeseburgers.
So, first step is to plug in y=4 in the given inequality. So,
2.50x+3.50(4)<30
2.50x+14 <30
2.50x<30- 14 Subtracting 14 from each sides.
2.50x< 16
Dividing each sides by 2.50.
x<6.4
Now x being number of hamburgers must be an integer , so tha maximum value of x can be 6,
thus x = 6 hamburgers
So, the maximum value of hamburgers Ben could have sold is 6*2.5=$15
Hope this helps!!
