Suppose you want to have $800,000 for retirement in 20 years. Your account earns 7% interest. Round your answers to the nearest cent.
a) How much would you need to deposit in the account each month?
$
b) How much interest will you earn?
$

So the first thing we do is to multiply the top equation by 3. the reason i want to do this is i notice there will be a 6y on both equations and can possibly add/subtract them. so we get 6y = -3x + 27. adding that and the second equation we get 6x = 27-15 which is 12. divide by 6 and we get 2. ∴ x = 2. substituting 2 into the first equation we get 2y = -2 + 9 which is 7. divide by 2 and we get 7/2. ∴ y = 7/2, x = 2.

Because the price would be 25% off the 25% off, which for example would be 25% off 20 dollars, which it would be 15 dollars. then, 20% off 15 dollars would be 11.25, and not 10.