Credit Cards In 1990, people charged $534 billion on the two most–used types of credit cards. In 1994, people charged $1.021 trillion on these same two types of credit cards. What was the rate of change?
2006-10-31 12:46:35 · 2 answers · asked by ~*bRiTtNaY*~ 2 in Science & Mathematics ➔ Mathematics
let x1 = 1990, x2 = 1994
let y1 = $534,000,000,000, y2 = $1,021,000,000,000
slope formula = (y2-y1)/(x2-x1)
= ($1,021,000,000,000 - $534,000,000,000)/(1994-1990)
= ($486,000,000,000/4)
= $121,750,000,000
So in conclusion the average rate of change from 1990 to 1994 is approximately $121,750,000,000 on the same two typically used credit cards.
2006-10-31 14:47:53 · answer #1 · answered by Chris 5 · 0⤊ 0⤋
Rate of change is change divide by Time
Amount of change is $1.021 Trillion which equals $1,021 billion minus $534 billion
$1,021 billion - $534 billion = $487 billion
Time from 1990 to 1994 is 4 years
so the rate of change is
$487 billion/4years = $121.75 billion/yr
2006-10-31 12:52:49 · answer #2 · answered by Alan C 1 · 0⤊ 0⤋