ASVAB CampPercentages flashcards
8 cards with the formulas, rules and traps from this lesson. Answer in your head, then flip to check.
Formula · 1/8
What are the three core percent relationships?
Part = percent times whole; percent = part divided by whole; whole = part divided by percent, with the percent written as a decimal. The whole usually comes right after 'of'.
Rule · 2/8
How do you convert between a percent and a decimal?
Percent to decimal: move the point two places left (7 percent is 0.07, 125 percent is 1.25, 0.6 percent is 0.006). Decimal to percent: move it two places right.
Formula · 3/8
What is the formula for percent change?
. Always divide by the original value: 50 rising to 65 is , a 30 percent increase.
Common trap · 4/8
After a 30 percent increase a budget is 182 thousand. What was the original?
Divide by the multiplier: thousand. Taking 30 percent off 182 (about 127.4) is wrong because the increase was figured on the original.
Rule · 5/8
What single multiplier handles a discount, a sales tax or a markup?
Discount: multiply by 1 minus the rate (15 percent off means times 0.85). Tax or markup: multiply by 1 plus the rate (6 percent tax means times 1.06).
Common trap · 6/8
500 rises 10 percent and then falls 10 percent. What is the result?
495, not 500. Multiply the factors in order: . The second change is taken from the new, larger amount.
Rule · 7/8
A 120 dollar radio is 20 percent off, then taxed 7 percent. Final cost?
Discount first, then tax the sale price: and , so 102.72 dollars.
Strategy · 8/8
How can you find percents mentally without a calculator?
Get 10 percent by moving the point one place left; 5 percent is half of that and 15 percent is their sum; 1 percent moves the point two places. Swapping helps too: 8 percent of 50 equals 50 percent of 8, which is 4.