Question

Sam opened a money-market account that pays 2% simple interest. He started the account with $7,000 and made no further deposits. When he closed the account, he had earned $420 in interest. How long did he keep his account open?
3 years
6 years
4 years
5 years

Answer 1

@cwrw238

Answer 2

help I will medal @chefducky

Answer 3

i dunno

Answer 4

@SyedMohammed98

Answer 5

@natsent06

Answer 6

For one year interest you use

0.02 times 7000=$140

1 year=140 interest

how many for 420 interest??

Answer 7

I don't know help @dtan5457

Answer 8

420 divided by 140 is..?

Answer 9

3

Answer 10

its 3 here the solution
ar(n)=total
a is the first number which is 7000
r is the common ratio which is 100%+2%=102 102 divided by 100 giving u 1.02(interest)
so ar(n)=sum n is written as power.....and is the number of years
so 7000*1.02(n)=(7000+420)
1.02(n)=7420/7000
1.02(n)=1.06
log10 1.02(n)=log10(1.06) ( multiply log10 with both)
n=log10(1.06)/log10 (1.02)
u get 2.94 which is round off to 3 so 3 years..
hope u get it :)

Answer 11

HAHA I DIED ^

Answer 12

lol