Answer:
a = 9
Step-by-step explanation:
Simplifying
8.1 = 0.9a
Solving
8.1 = 0.9a
Solving for variable 'a'.
Move all terms containing a to the left, all other terms to the right.
Add '-0.9a' to each side of the equation.
8.1 + -0.9a = 0.9a + -0.9a
Combine like terms: 0.9a + -0.9a = 0.0
8.1 + -0.9a = 0.0
Add '-8.1' to each side of the equation.
8.1 + -8.1 + -0.9a = 0.0 + -8.1
Combine like terms: 8.1 + -8.1 = 0.0
0.0 + -0.9a = 0.0 + -8.1
-0.9a = 0.0 + -8.1
Combine like terms: 0.0 + -8.1 = -8.1
-0.9a = -8.1
Divide each side by '-0.9'.
a = 9
Simplifying
a = 9
6(2(5) - 4)
6(10 - 4)
6(6)
36
a) (0.17 ac)×(126 min/ac) = 21.42 min
b) I can mow 1/126 ac/min; you can mow 1/117 ac/min. Together, we can mow at a rate that is the sum of these:
... (1/126 + 1/117) ac/min = (117 + 126)/(126×117) = 243/14,742 ac/min
Then it will take 14,742/243 min/ac × 0.17 ac/lawn ≈ 10.31 min/lawn
Answer:
Step-by-step explanation:
<u>Total number of outcomes:</u>
<u>Number of combinations of getting 6 heads:</u>
- 15C6 = 15!/6!(15-6)! = 5005
<u>Required probability is:</u>
- P(6 heads out of 15 flips) = 5005/32768 = 0.1527... ≈ 15.3%
Correct choice is D
Solution: The speed of old freight train is 0.5 miles per minute and the speed of new dart express train is 1.5 miles per minute.
Explanation:
Let the speed of old freight train is x miles per minute and the speed of new dart express train is y miles per minute.
It is given that the speed of the dart express train is three times faster than the freight train. So, it can be written as,
....(1)
The trains are moving towards the opposite directions, therefore the distance between them is increased at the speed of 
miles per minute.
The distance between both train in 15 minutes is represented by 
.
According to the given information the distance between trains is 30 miles in 15 minutes.
Use equation (1) and put 
Put this value in equation (1), to find the value of y.
Therefore, the The speed of old freight train is 0.5 miles per minute and the speed of new dart express train is 1.5 miles per minute.
