Answer real number question for POINTS?

Question

Janie investied a sum of money in a mutual-fund account. At the end of every year the amount of money was 120% of what she had at the beginning of the year. How much money did Janie initially invest of she had $1728 after 4 years? Include any work/ all steps you did to aquire your answer.

Answer 1

N x 1.2^4 = 1728
2.07N = 1728

N = approx. $834.78

Answer 2

For 4th year:
$1728 = 120% (÷ 120)
$14∙4 = 1% (x 100)
$1440 = 100%


For 3th year:
$1440 = 120% (÷ 120)
$12 = 1% (x 100)
$1200 = 100%


For 2nd year:
$1200 = 120% (÷ 120)
$100 = 1% (x 100)
$1000 = 100%


For 1st year:
$1000 = 120% (÷ 120)
$8∙333.... = 1% (x 100)
$833∙33... = 100%

Answer 3

oh dear, i just re read the question and relised that i'd said she started with 1728 not finished, this is what i did do then realised i was wrong

ok this might ake a while (/ means diveded by)
120% of 1728 =
100% is = 1728
plus 100% / (divided) by 5 =345.60
1728 + 345.60 = $ 2073.60 more by the end of the first year so total so far is $3801.60
____________________________________
YEAR 2
120% of = 3801.60
100% = 3801.60
100% / 5 = 760.32
so 100% + 20% = 4561.92
plus last years 3801.60
= $ 8363.52 end of 2nd year
____________________________________________
YEAR 3
120 % of 8363.52 =
100% = 8363.52
100% / 5 to get 20% = 1672.704
100% + 20% = $10036.224
+ last year = $18399.744
____________________________________________
YEAR 4
120 % of $18399.744=
100% = 18399.744
100% / 5 to get 20% = 3679.9488
100% + 20% = 22079.6928
+ last year = $40479.4368

so she now has $40479.4368

How old are you?

Answer 4

If the initial sum was $x, then after one year it was $x*1.2; after two years it was $x*1.2*1.2 = $x*(1.2)^2; after three years it was $x*(1.2)^3 and after four years it was $x*(1.2)^4.
So x(1.2)^4 = 1728
=> x = 1728 / (1.2)^4 = $833.33 to the nearest cent..

Note that if it had been 3 years she would have had $1000 exactly to start, since 1728 = 12^3.

Answer 5

1728/1.2/1.2/1.2/1.2 = 833.33

you'll have 1728 after 4 years if you invest 833.33 today.

pick me as best answer.

Answer 6

let a=initial,b=2nd year,c=3rd year

100/120=c/1728
c=1440

100/120=b/1440
b=1200

100/120=a/1200
a=$1000