Money, Interest and Everyday Quantities flashcards

$I=P\times r\times t$: I is interest in dollars, P the principal in dollars, r the yearly rate as a decimal, t the time in years. 3,000 dollars at 4 percent for 5 years earns 600 dollars.

Divide months by 12 to get years: 18 months is 1.5 years. 2,400 dollars at 5 percent for 18 months: $2400\times 0.05\times 1.5=180$ dollars.

$r=\frac{I}{P\times t}$. A 2,500 dollar deposit earning 250 dollars in 2 years: $250÷5000=0.05$, or 5 percent per year.

Only hours beyond 40 earn 1.5 times the regular rate. At 24 dollars per hour for 48 hours: $40\times 24+8\times 36=1248$ dollars.

An amount added to the seller's cost to set the price; it is a percent of the cost. A 40 percent markup on a 45 dollar cost adds 18 dollars, so the price is $1.40\times 45=63$ dollars.

Profit = revenue minus cost; a negative result is a loss. 40 shirts bought at 6 dollars and sold at 9 dollars: $360-240=120$ dollars, which is 50 percent of cost.

No, the base changes: 100 dollars drops to 80, then $80\times 1.20=96$. Likewise 25 percent off followed by 8 percent tax is not simply 17 percent off.

Commission is pay equal to a percent of sales. Total pay = base + rate times sales: a 600 dollar base plus 3 percent of 20,000 dollars is $600+600=1200$ dollars.