general maths question help

reems

hi! I dont know what im doing wrong but how can I get the right answer for these. im using financial solver

1- Mariska plans to retire from work 10 years from now. Her retirement goal is to have a balance of $600 000 in an annuity investment at that time. The present value of this annuity investment is $265 298.48, on which she earns interest at the rate of 3.24% per annum, compounding monthly.
To make this investment grow faster, Mariska will add a $1000 payment at the end of every month.
Two years from now, she expects the interest rate of this investment to fall to 3.20% per annum, compounding monthly. It is expected to remain at this rate until Mariska retires. When the interest rate drops, she must increase her monthly payment if she is to reach her retirement goal.
The value of this new monthly payment will be closest to
A. $1234
B. $1250
C. $1649
D. $1839

E. $1854

2- Adam has a home loan with a present value of $175 260.56. The interest rate for Adam's loan is 3.72% per annum, compounding monthly. His monthly repayment is $3200. The loan is to be fully repaid after five years. Adam knows that the loan cannot be exactly repaid with 60 repayments of $3200. To solve this problem, Adam will make 59 repayments of $3200. He will then adjust the value of the final repayment so that the loan is fully repaid with the 60th repayment.
The value of the 60th repayment will be closest to
A. $368.12
B. $2831.88
C. $3200.56
D. $3557.09

E. $3568.12

3- Twenty years ago, Hector invested a sum of money in an account earning interest at the rate of 3.2% per annum, compounding monthly. After 10 years, he made a one-off extra payment of $10 000 to the account. For the next 10 years, the account earned interest at the rate of 2.8% per annum, compounding monthly. The balance of his account today is $686 904.09.
The sum of money Hector originally invested is closest to
A. $355 000
B. $370 000
C. $377 000
D. $384 000
E. $385 000

FH ⭐️

question 3 was a huge pain to get the answer, but here is how i approached all 3 questions.
remember when using finance solver, having a (-) sign means that the money is not in the possession of the person (for example, in an annuity investment the person doesn’t have the money on them therefore is a negative, or if someone is making a payment then it’s negative because the money is going away from the person).

anything italicised in my workings out is the value we are finding in finance solver.

question 1

first, you need to find the value of the annuity after two years before the interest rate drops
to do this, find the FV

N: 2x12
I: 3.24
PV: -265298.48
Pmt: -1000
FV: 307794.50
P/CpY: 12

next, we have to find the new payment as the interest rate has dropped
we have to consider the annuity needs to reach $600,000 in 8 more years, as 2 years have already passed (2+8=10)
the PV is now the FV from the first half of the question, but needs to be negative because the person does not yet have the money
to do this, find the Pmt

N: 8x12
I: 3.20 (remember to change this)
PV: -307794.50
Pmt: -1854.05
FV: 600000
P/CpY: 12

therefore, your answer should be E

question 2

first, you need to find how much of the loan is left after 59 payments.
to do this, find the FV

N: 59
I: 3.72
PV: 175260.56
Pmt: -3200
FV: -3557.09
P/CpY: 12

next, you change the N value to 1, as this is the final payment
FV will be zero as the loan will be paid out
PV becomes the FV value from the first half, but remove the (-) as the person still has that amount from the loan
to find the final payment, find for Pmt

N: 1
I: 3.72
PV: 3557.09
Pmt: -3568.12
FV: 0
P/CpY: 12

therefore, your answer should be E

question 3

this question requires you to work backwards which can be super annoying
you should start by finding the value of the investment 10 years before the one-off payment (so 10 years after the investment began)
to do this, you need to use the value of the investment after 20 years ($686904.09) as the FV, and solve for the PV
you will use the 2.8% interest rate as this is the SECOND half of the investment

N: 120
I: 2.8
PV: -519320.30
Pmt: 0
FV: 686904.09
P/CpY: 12

next, you need to do the one off $10000 payment, where you use the PV from the working out above and subtract $10000

519320.30 - 10000
= 509320.30

finally, that value becomes the new FV and should be without the (-), as the person will have that money if they took out the investment after 10 years
change the interest rate to 3.2% as this is the first 10 years we are solving for
to find the initial value of the investment, solve for PV

N: 120
I: 3.2
PV: 369999.99
Pmt: 0
FV: 509320.20
P/CpY: 12

$369999.99 is closest to $370000, therefore your answer should be D

reems i hope this helps, let me know if you have more questions!!

reems

thank you so much! I must of been getting my - mixed up with pmt and pv and the rest of it, I have notes on it for example it says annuity should be PV; negative, everything else positive, but question 1 was PV and pmt negative, but it was in the question! Makes sense now, thanks!