A = P + I = P + Prt = P (1+rt) ?Why are there multiple versions for finding A?

Question

parthkohli · Answer

Because there are many ways to solve a problem.

But all of them mean the same thing.

parthkohli · Answer

P + I = P + PRT because I = PRT.

parthkohli · Answer

Just apply yourself and see what you are comfortable with.

anonymous · Answer

well if they all mean the same i get different conclusions with them I'll show you what I mean.

anonymous · Answer

For instance, A person borrows $ 1000 for a period of 6 months. What simple interest rate is being charged if the amount A that must be repaid after 6 months is $ 1045.

anonymous · Answer

The formula in textbook used A = P + Prt so that is  1045 = 1000 +1000r(1/2) ... that leads to 45 = 500r and then r becomes...09. However if i used A = P ( 1+rt) the awnser i got was different.

anonymous · Answer

i got.. r = 1045/1500..which means r = .69...

anonymous · Answer

D: i don't understand...

parthkohli · Answer

$$A = P(1 + RT)$$$$\Rightarrow 1045 = 1000(1 + 0.5R)$$$$\Rightarrow 1045= 1000 + 500R$$$$\Rightarrow500R = 45$$

parthkohli · Answer

Also, $P+PRT = P(1 + RT)$ because we have factored the $P$ out.

anonymous · Answer

wait.. shouldn't (1+0.5) 1.5 ... 1.5 (1000) is 1500? how did you get 500?

anonymous · Answer

i thought it was 1045 = 1500r =T

parthkohli · Answer

That is $0.5R$, not $0.5$.  We know that $T =0.5$.$$P(1 + RT) = P(1 + 0.5R) = 1000(1 + 0.5R) = 1000 + 500R$$

anonymous · Answer

sorry.. i still don't understand.. T_T... for some reason i can't get 500r T_T

anonymous · Answer

i feel so stupid..T_T

parthkohli · Answer

$$1000(1 + 0.5R)$$Do you get it till here?

the_fizicx99 · Answer

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