Mary has $65,000 to invest in two accounts. The first account is a private savings offering 6% annual interest and the second account is a government savings account offering 4% annual interest. How much money should Mary invest in each account to make $3520 in total annual interest.

first account with 6% interest ( x ) = $46000

second account with 4% interest ( y ) = $19000

Step-by-step explanation:

Principal = $65000

first interest rate = 6%

second interest rate = 4%

assuming ; X = money invested in first account ,  Y = money invested in second account

hence :

( 65000 - y ) * 6% + ( 65000 - x ) * 4% = 3520

3900 - 0.06 y  + 2600 - 0.04 x = 3520

0.04 x + 0.06 y = 3900 + 2600 - 3520

0.04 x + 0.06 y = 2980 ( 1)

        x + y = 65000   ( 2 )

solve equation 1 and 2 simultaneously by elimination method

0.04 x + 0.06 y = 2980  ( 3 )

0.06 x + 0.06 y = 3900 ( 4 )

subtract equation 3 form equation 4

0.02 x  = 920 ,   hence x = $46000

therefore y = $65000 - $46000 =  $19000

let's add {f(x)=x+1}f(x)=x+1 and {g(x)=2x}g(x)=2x together to make a new function.

f(x)+g(x) =(x+1)+(2x)=x+1+2x=3x+1

let's call this new function hh. so we have:

{h(x)}={f(x)}+{g(x)}{=3x+1}h(x)=f(x)+g(x)=3x+1

we can also evaluate combined functions for particular inputs. let's evaluate function hh above for x=2x=2. below are two ways of doing this.

method 1: substitute x=2x=2 into the combined function hh.

h(x)

h(2)

​    

=3x+1

=3(2)+1

=7

​ since h(x)=f(x)+g(x)h(x)=f(x)+g(x), we can also find h(2)h(2) by finding f(2) +g(2)f(2)+g(2).

first, let's find f(2)f(2):

f(x)

f(2)

​    

=x+1

=2+1

=3

​  

now, let's find g(2)g(2):

g(x)

g(2)

​    

=2x

=2⋅2

=4

​  

so f(2)+g(2)=3+4=\greend7f(2)+g(2)=3+4=7.

notice that substituting x =2x=2 directly into function hh and finding f(2) + g(2)f(2)+g(2) gave us the same answer!

total amount to be paid = $19.5

step-by-step explanation:

given ,

original price = $25.99

discount = 25%

discount amount = 25% of original price

discount amount = 25/100   * 25.99

discount amount = $6.49

hence , the total amount to be paid = original price - discount amount

                                                            = $25.99 - $6.49

                                                            =$19.5

total amount to be paid = $19.5