A sum of $4000 is invested at 5.5% interest per year. Find the amount of time needed to double the money if it’s compounded monthly. A) 12y
B) 12y 4m
C) 12y 8m
D) 13y

9514 1404 393

  C)  12y 8m

Step-by-step explanation:

The amount of principal P at compound monthly at interest rate r per year is given by ...

  A = P(1 +r/12)^(12t) . . . . after t years

Here, we want to find t, so ...

  A/P = (1 +r/12)^(12t)

  log(A/P) = (12t)·log(1 +r/12)

  t = log(A/P)/(12·log(1 +r/12))

Filling in the given values, we find t to be ...

  t = log(8000/4000)/(12·log(1 +0.055/12)) ≈ 12.6315 ≈ 12 years 7.6 months

It will take about 12 years 8 months to double the money.

to find the perimeter of the rectangle this is the expression:

x-9+x-9+3x-4+3x-4=138

if we simplify it:

8x-26=138

remember, 138 is what it all adds up to

the length is 11.5cm

the width is 57.5cm

the area is 661.25cm^2

the answers might not be correct use at own risk

system of linear equation

step-by-step explanation:

as given in the data

a= 20 , b= -12

let us suppose that it is a straight line equation

now we know the formula for the system of linear equation

b= ma + c )

here m is slope of a straight line which is equal to formula

m=   (ii)

and here c is a constant

now putting the value of a and b in equation (ii)

m=

m=

putting the value of a,b and m in equation (i) gives us

-12 = + c

-12=-12 + c

adding 12 to both sides

-12 +12 = -12 +12 +c

0 =c

or c=0

as the value of the constant is zero which gives us that it is a linear equation and this order pair satisfies the system of linear equations.