On Fumiya's tenth birthday, his grandfather deposited $40 in a savings account for him. Each year, his grandfather
deposited twice the amount of the previous year's deposit.
How much money did his grandfather deposit in the account
on the day Fumiya turned eighteen?
A $7200
B $17,920
C $13,500
D $10,240

third option: 6x+8

step-by-step explanation:

we can see that the given question is a sum of series and the values of n vary from 0 to 3

the first term will be:

when n=0, [(0)*x+2] => (0+2) => 2

when n=1, [(1)*x+2] => (x+2) => x+2

when n=2, [(2)*x+2] => 2x+2

when n=4, [(3)*x+2] => 3x+2

so adding up all the terms will give us:

=2+x+2+2x+2+3x+2

=x+2x+3x+2+2+2+2

=6x+8

so,

third option is the correct answer ..

step-by-step explanation:

left be aligning the decimal points is required to not required see the number of digits to the right

the answer is 15 to your question