Lucinda put $66 into a cd that pays 5.7% interest. according to the rule of 72, approximately how long will it take for her money to double?

13 years

Step-by-step explanation:

It is given that,

Lucinda put $66 into a CD that pays 5.7% interest. According to the rule of 72,  

The rule of 72  

It is a simplified way to determine, If we invest some amount, how long that investment will take to double,

Formula

Let R be the rate of interest,

The time required to take double the amount = 72/R

Calculate the approximate years

According to the rule of 72, approximately 12.63 ≈ 13 years will it take for her money to double

c. 4 1/4 pounds

geometric series converge the common ratio r has magnitude less than one.

which is equivalent to

for the example we need

|2-x| < 1

-1 < 2-x   and 2-x < 1

x < 3 and x > 1

we can write that

answer: 1 < x < 3

1a. common ratio r=250/25=10 > 1     diverges

1b.   r=50/100=1/2 converges

when these converge they converge to

where a is the first term.

answer: 200

1c. r=-1   so it's not the case that |r| < 1.     diverges

2a. x is the common ratio so we converge when |x|< 1

2b.   r=-10x / -2 = 5x.

we converge when

|5x| < 1

|x| < 1/5

2c.   r=3-2x

-1 < 3-2x and 3-2x < 1

-4 < -2x and 2 < 2x

x < 2 and 1 < x

1 < x < 2

2d. [/tex] r=-48x^3/12 = 4x^3[/tex]

|4x^3| < 1

|x^3| < \frac 1 4

|x| < 4^{-1/3}