Answer:
700 lei
Step-by-step explanation:
You have a geometric sequence for which you know the common ratio and the last term.
There are only three terms, so you can solve the problem in either of two ways.
1. The brute force method
(easiest for only a few terms)
Each term is half the one before it, so each term is double the one after it.
3rd term = 100 lei
2nd term = 200
1st term = 400
Total = 700 lei
Oana spent 700 lei
2. Using formulas (best for longer sequences)
The general formula for your sequence is
aₙ = a₁rⁿ⁻¹
For your sequence,
a₃ = 100; r = 0.5
(a) Calculate a₁
Set the last term equal to the general formula.
a₃ = a₁(0.5)ⁿ⁻¹
100 = a₁(0.5)² = 0.25a₁
a₁ = 100/0.25 = 400
(b) Calculate the sum
The general formula for the sum of a geometric sequence is
Oana spent 700 lei.
Answer:
30
Step-by-step explanation:
Answer:
Step-by-step explanation:
The surface area of the prism consists of four rectangles and two trapezoids. The sum of the areas of these polygons will give the total surface area of the prism:
Rectangle 1 (top base):
Rectangle 2 (bottom base):
Trapezoids 1 and 2 (lateral):
Rectangles 3 and 4 (lateral):
Thus the total surface area is equal to
Answer:
-47
Step-by-step explanation:
remove unnecessary parentheses
-4-44-(-1)
calculate the sum or different
-47
When you convert anything to something else, they both must have the same "physical dimensions". That means they both must be the same kind of quantity. You can convert a length unit to a different length unit, or an area unit to another area unit. Like feet to inches, or quarts to gallons, or days to weeks.
"Meter" is a unit of length. "Second" is a unit of time. There is no way to convert length to time or time to length.
If you could convert length to time, then you'd be able to calculate how many minutes tall you are.
And if you could convert time to length, then you'd be able to calculate how many yards of sleep you got last night.
Both of those are pretty silly. Length and time can't be converted to each other.