Answer: See explanation
Step-by-step explanation:
Your question isn't well written but I saw an identical question:
A bookshelf is 42 inches long. Each book is 1 1/4 inches wide. How many books will fit on the shelf?
For us to solve this, we would divide the length of the bookshelf by the width of each book. This would be:
= 42 ÷ 1 1/4
= 42 ÷ 5/4
= 42 × 4/5
= 33 3/5
Therefore, the number of books that will fit on the shelf is 33.
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 <<<<<
1.
a.) 2q + 5r
2(7) + 5(-2)
14 - 10 = 4
b.) 3(p + 6) + q + r Plug in the numbers
3(5 + 6) + 7 - 2 Solve inside the parentheses first
3(11) + 7 - 2
33 + 5 = 38
2.
a.) m(3m + 4n)
2(3(2) + 4(3))
2(6 + 12)
2(18) = 36
b.) n²(m + p²)
(3)²(2 + (-5)²)
9(2 + 25)
9(27) = 243
c.) 3m(8 + n) + n²
3(2) (8 + 3) + 3²
6(11) + 9
66 + 9 = 75
The formula for Average speed = 
The car travels 80 km in 1 hour.
Then the car travels 90 km in 2 hours.
And finally the car travels 76 km in 1 hour
So the total distance covered by the car = 80 + 90 + 76 = 246 km
The total time taken to cover this distance = 1 + 2 + 1 = 4 hours.
So average speed = 
The average speed of the car is 61.5 km / h
Answer:
580
Step-by-step explanation:
4*100=400
4*40=160
4*5=20
add them all up, you get 580
