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:
5.1
Step-by-step explanation:
you need to work backwards.
so do 17.5 + 8 then divide by 5 to get 5.1
i hope this helps :)
<h3><u>Solution: </u></h3>
Radius of Cylindrical Pillar , r = 28 Cm = 0.28 m.
Curved surface area of a Cylindrical = 2πrh.
Curved surface area of a pillar -
Curved surface area of 24 such Pillar :-
(7.04 x 24 = 168.96m²)..
- Cost of painting an area of 1 m² = Rs8...
• Therefore , cost of painting 1689.6m² :-
( 168.96 x 8 = Rs 1351.68)...
You only need a common denominator for adding and subtracting! <span />
Answer:
it is easier to multiply first and then to place the decimal point. Multiply the factors as if they were whole numbers. Disregard the decimal point until you place it in the product.
