Answer:
$265.07
Step-by-step explanation:
The formula for the future value of an annuity is applicable.
A = P((1+r)^n-1)/r . . . . where r is the monthly interest rate and n is the number of months. P is the monthly payment, and A is the amount of the future value.
800 = P(1.006^3 -1)/(.006) = 3.018036P
P = 800/3.018036 ≈ 265.07
Sarafina's monthly payments need to be $265.07.
_____
This is about $1.60 less than the 266.67 she would deposit if she simply divided the desired balance by the number of months.
Because this number is rounded down, Sarafina will have a balance after 3 months of $799.99.
<h2>a. Answer:</h2>
For this question we'll use the following method:
1. Let's subtract old value from new value
185$-160$ = -25$
The negative value implies that the price has decreased
2. Divide the result by the old value
25$/185$ = 0,1351
3. Convert this value to percentage:
0,1351 x 100 = 13,51%
Finally, by rounding to the nearest tenth:
13,5%
That means 13,5% decrease
<h2 /><h2>b. Answer:</h2>
1. Let's subtract old value from new value
77$-56$ = 21$
The positive value implies that the price has increased
2. Divide the result by the old value
21$/77$ = 0,2727
3. Convert this value to percentage:
0,2727 x 100 = 27,3%
Finally, by rounding to the nearest tenth:
27,3%
That means 27,3% increase
This kind of problem request the use of harmonic mean:
if t₁ is the Time spent by Jessica, and
t₂, the time spent by Felecia, and t₃ the time spent by both, then the equation of that kind of problem will be:
1/t₁ + 1/t₂ =1/t₃.
t₁ = 1h45 min, t₂ (unknown, to be calculated), t₃ = 1 h, to ease things let' convert the time in minutes
t₁ = 105 min
t₂ = ?(time needed to Felicia to maw the lawn)
t₃ = 60 min
1/105 +1/t₂ = 1/60===> 1/t₂ = 1/60 - 1/105==> 1/t₂ =1/140
& t₂ =140 minutes or t₂ = 2h & 20 min