Ateam of scientists estimate the current number of butterflies in a park to be 20 thousand. the butterfly population is expected to increase at a rate of 4% per year. which equation models the number of butterflies, in thousands, in the park after n years?

 Current number of butterflies in the park = 20 thousand.

 Rate of increase of butterfly population = 4% = 0.04

The population of butterfly after 1 year = 20+0.04*20 = 20*1.04

The population of butterfly after 2 years =  20*1.04 + 20*1.04*0.04 = 20*1.04*1.04

 The population of butterfly after 3 years =  20*1.04*1.04 + 20*1.04*1.04*0.04 = 20*1.04*1.04*1.04

So, population of butterfly after n years = 20*(1.04*1.04*1.04* n times)

Step-by-step explanation:

This will be an exponential growth equation, of the form

,

where a represents the initial population, r represents the rate of growth per year, and x represents the number of years.

The initial population is 20,000.  This goes in place of a.

The rate of growth is 4%.  4% = 4/100 = 0.04; this goes in place of r.

We are using n to represent years instead of x.

This gives us

Adding in parentheses gives us

check above link.

graphically?   well, you graph them both, the solutions is where they both intersect each other, since there are two solutions, meaning they will meet twice, or namely the linear will run into the quadratic curve twice, and where they meet, those x,y coordinates are the solutions to the system.

if gloria has "carry over" minutes, (that is, any minutes paid for but not used in a month can be applied to her payment for minutes in the next month,) her total usage for the three months is: total minutes = 320 + 243 + 489 = 1052 minutes number of 200 minute blocks = 1052/200 = 5 r52 (that is 5 with a remainder of 52) rounding up the number of 200 minute blocks gives her usage for the three months as 6 blocks. the cost for six blocks is 6 x $25 = $150 she also has 200 - 52 or 148 carry over minutes if gloria pays each month and unused minutes are lost, applying the rounding up procedure to each month gives: first month usage of 320 minutes rounds up to 2 blocks of 200 minutes for a payment of 2 x $25 = $50 second month usage of 243 minutes rounds up to 2 blocks of 200 minutes for a payment of 2 x $25 = $50 third month usage of 489 minutes rounds up to 3 blocks of 200 minutes for a payment of 3 x $25 = $75 total payments for the three months are $50 + $50 + $75 = $175 get the plan with carry over minutes!