177.55500 kilometers and i yw ;)
Answer:
He can fit 2 more DVD's on the shelf.
And he'll have about 12 mm of extra space left.
Step-by-step explanation:
40×1.4 = 56cm This is the length of space the 40 DVD's will take up.
60-56 = 4cm This is the amount of space left.
4/1.4 = 2.857 the number of DVD's that will fit.
Of course, the decimal represents a partial DVD which is worthless.
Just to be sure, 2×1.4 = 2.8cm OK. But 3×1.4= 4.2cm which is 2mm too much
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.
Consider ΔAQD. This triangle has the area
where H is the heigh drawn from the point Q to the side AD.
Note that the height H is also the height of the parallelogram. So the area of the parallelogram ABCD is
From these two statements you can conclude that
Now consider ΔDMQ. The ratio between the area of triangles DMQ and AQD is
Since you have that
and
Thus,
Answer: correct choice is B