What is the formula for the nth term of the given sequence 100, 20, 4, …

Mathematics

1 answer:

Naily [24]2 years ago

6 0

Answer:

$a_n=100 \left(\dfrac15\right)^{n-1}$

Step-by-step explanation:

General equation of geometric sequence: $a_n=ar^{n-1}$

Given:

a₁ = 100
a₂ = 20
a₃ = 4

$\implies a_1=a=100$

$\implies a_2=100 \cdot r=20$

$\implies a_3=100 \cdot r^2=4$

Common ratio:

$r=\dfrac{a_3}{a_2}=\dfrac{4}{20}=\dfrac15$

Therefore:

$a_n=100 \left(\dfrac15\right)^{n-1}$

You might be interested in

A patrolman spends 25% every day completing paperwork. The patrolman’s shift each day is 8 hours. How much of his time does he s

fredd [130]

Assuming the man works 8 hours straight without breaks:

25% is the same as 1/4 of something.

So, we just have to figure out what 1/4 (one quarter) of 8 equals.

You can think of it as a pizza cut into 8 slices. One slice is equivalent to one hour for the patrolman.

If we take away 1/2 (half) of the pizza, we have 4 slices, right? Since we start with 8 slices, half of that equals 4 slices. In other words, 50% (half) of the pizza = 4 slices.

Now, 25% (one quarter) of the pizza will equal half of what is left:

If we know that 50%=4 slices (or 4 hours), then 25% must be 2 slices (or 2 hours).

That's it! 25% of 8 hours = 2 hours.

***So, the patrolman spends 2 hours each day completing paperwork.***

Lets check our work:
We know 8 hours (or 8 slices)= 100%
(We know this because
8 slices = 1 whole pizza, or 100% of a pizza. Similarly,
8 hours = 1 whole shift or 100% of the man's shift ).

So

25% + 25% + 25% + 25% = 100%

If 100% of the mans shift = 8 hours:

2+2+2+2 = 8

It checks out!

Hope this helps!

4 0

4 years ago

Tell what number you would add to each side of the inequality.<br> Please answer ASAP

Zinaida [17]

Answer: 6

Step-by-step explanation: Gets x by itself.

8 0

3 years ago

How do i turn 3/8 into a decimal

vodomira [7]

Divide 3 by 8! So your answer would be 0.375! :)

6 0