if there was a 15% discount, then you paid 75% of the original price. Since we don't know the orginal price, we will assign it the variable x. Change 75% to a decimal. The equation would be:
.75x = 208.25 To get the variable by itself, divide each side by .75
If the population quadruples every period say hour, that means the "rate of growth" is 300%, so whatever the current amount, increased by 3 times as much is 4 times the current amount, or a quadrupled amount.
