Word Problem

Dracula has already bitten 3 people. Everyday he gets 2 more victims. Johnathan Harker and Dr. Abraham Van Helsing combined have already slain 2 vampires. Harker and Van Helsing are becoming more skilled as time progresses and are now killing 3 vampires everyday. After how many days will Harker and Van Helsing catch up to Dracula?

Solve:

write the equations: y equalls the number of vampires while x equals the days

y = 3x + 2

y = 2x + 3

use the elimination method to solve: mulitply the first equation by -2 and the second by 3

-2y = -6 + -4

3y = 6x + 9

add the equations

-2y = -6 + -4

+ 3y = 6x + 9

y = 5

plug y back into one of the orginal equations to find x

5 = 2x + 3

solve for x

x = 1

answer: since x equals the number of days and x = 1, then after 1 day Harker and Van Helsing have killed the same number of vampires as Dracula has made

Hompage / Graphing / Substitution / Elimination