Liam opened a savings account with a $400
deposit and a simple interest rate of 7.5%. If
the balance of the account is now $670 and
there were no deposits or withdrawls, how
long ago did he open the account

he open the account 9 years ago.

Step-by-step explanation:

The formula for determining simple interest is expressed as

I = PRT/100

Where

I represents interest paid on the amount deposited.

P represents the principal or amount deposited.

R represents interest rate

T represents the time for which the amount deposited was left in the account.

From the information given,

P = 400

R = 7.5%

I = 670 - 400 = $270

Therefore,

270 = (400 × 7.5 × T)/100 = 30T

T = 270/30

T = 9 years

$3720

step-by-step explanation:

taxable income = $31000

as per the 2018-2019 us tax bracket, the tax rate is 12% for an individual whose taxable income is between $9,526 to $38,700.

so, the tax to be paid by him = 12% of 31000

= 0.12 * 31000     [12% converted to decimal as 0.12]

= $3720