marsha waide borrows 5,000 and agrees to pay it back in 2 years . if the simple interst rate is 13% ,find the total amount she pays back

You want to calculate the interest on $5000 at 13% interest per year after 2 year(s).

The formula we'll use for this is the simple interest formula.

Where:

P is the principal amount, $5000.00.

r is the interest rate, 13% per year, or in decimal form, 13/100=0.13.

t is the time involved, 2year(s) time periods.

So, t is 2year time periods.

To find the simple interest, we multiply 5000 × 0.13 × 2 to get that:

The interest is: $1300.00

Usually now, the interest is added onto the principal to figure some new amount after 2 year(s),

or 5000.00 + 1300.00 = 6300.00. For example:

If you borrowed the $5000.00, you would now owe $6300.00

step-by-step explanation:

12: 00 p.m. to 7: 00 p.m. is a total of 7 hours.

4: 00 p.m. to 7: 00 p.m. is a total of 3 hours.

this means that from 4: 00 p.m to 7: 00 p.m. this represents 3/7 of what was lost from 12: 00 p.m. to 7: 00 p.m.

after knowing this, after doing 11,600 - 6,800 = 4,800

4,800 represents 3/7 of what was lost for 7 hours.

we then divide 4,800 by 3 which gets 1,600.

because we know that 1,600 represents 1/7 of how much water was lost, we just have to multiply by 7, which gets 11,200.   after adding 11,200 to how much water was left at 7: 00 p.m. which was 6,800. 11,200 + 6,800 = 18,000

this means that the pool originally had 18,000 gallons in the pool.

you can also check your work by doing 18,000 - 4(1600), which becomes           1800 - 6400 which gets you 11,600.