Answer:
40/9
Step-by-step explanation:
Use the work formula, +
=
, where A is the amount of time it takes one person, B is the amount of time it takes another person, and T is the time it takes for them to work together.
Plug in the times for David and Alex alone:
+
=
Find the least common denominator, which is 40.
+
=
=
Cross multiply and solve for T:
9T = 40
T = 40/9
So, if they worked together, it would take them 40/9 hours
Answer: 1:1
Step-by-step explanation:
Let r be the radius and h be the height of a cylinder.
Formula: Curved surface area of cylinder =
Now, if radius of a cylinder is doubled and its height is halved, then new radius will be R= 2r and new height will be
Now, new surface area =
Ratio of curved surface areas :
Hence, the ratios of their surface areas = 1:1 .
Answer:
-7/2
Step-by-step explanation:
The slope of a line can be defined as: , which can be more formally calculated as:
, where it's essentially the same thing, except the rise/run is being calculated with two points (which you already need)
So let's just say:
Plugging the values into the equation we get:
You can also just look at the graph and see that from point 1 to point 2, it "rised" -7 units, and "ran" 2 units.
Notice how the "rise" is negative? That just means it went down.