Formula Review
6.1 Understanding Percent
part = percent x total
6.2 Discounts, Markups, and Sales Tax
discount=percent discount×original price
sale price=original price-discount
sale price=original price-percent discount×original price=original price×(1-percent discount)
markup=percent markup×cost
retail price=cost+markup
retail price=cost+percent markup×cost=cost×(1+percent markup)
sales tax=purchase price×tax rate
Total price=purchase price+purchase price×tax rate=purchase price×(1+tax rate)
6.3 Simple Interest
I=P×r×t
T=P+I
T=P+P×r×t
I=P×r365×t
FV=P+I=P+P×r×t
A=P×r×(1+r)t(1+r)t−1
PV=FV(1+rt)
6.4 Compound Interest
A=P(1+rn)nt
PV=A(1+rn)n×t
Y=(1+rn)n-1
6.6 Methods of Savings
A=P(1+rn)nt
ROI=FV-PP
FV=pmt×(1+r/n)n×t-1r/n
pmt=FV×(r/n)(1+r/n)n×t-1
6.7 Investments
annual return=(FVP)(1t)-1
P/E=Share PriceDividend
Yld%=Annual DividendShare Price×100%
6.8 The Basics of Loans
I=P×rn
pmt=P×(r/n)×(1+r/n)n×t(1+r/n)n×t−1
6.9 Understanding Student Loans
funding gap=total cost−all aid
A=P(1+rn)nt
pmt=P×(r/n)×(1+r/n)n×t(1+r/n)n×t−1
discretionary income=gross income−1.5×poverty guideline
6.10 Credit Cards
I=ADB×r×d365
6.11 Buying or Leasing a Car
pmt=P×(r/n)×(1+r/n)n×t(1+r/n)n×t−1
MD=P−Rn
APR=2400×MF
MF=APR/2,400
PMT=(P−R)n+(P+R)×MF
6.12 Renting and Homeownership
pmt=P×(r/12)×(1+r/12)12×t(1+r/12)12×t−1
T=pmt×12×t
CoF=T−P