Grace placed 3 strands bacteria in a petri dish. the bacteria strands triple every hour. write a formula to
represent at the nth hour. then use the formula determine how many strands of bacteria are represent
at 4 hours.

a) The growth of bacteria at nth hour is :

b) At the end of the fourth hour, there are 81 stands of the bacteria    

    present.

Step-by-step explanation:

The number of initial bacteria in the dish = 3 strands

Rate at which bacteria multiply = 3 times every hour

So, the general form which represents the growth

As it multiplies three times every hour, so at nth hour:

The growth of bacteria at nth hour is :

Now, at n = 4, the growth of the bacteria is  

= 3 x 3 x 3 x 3

⇒ = 81

So, at the end of the fourth hour, there are 81 stands of the bacteria present.

7

step-by-step explanation:

3

step-by-step explanation:

in standard form:

a= dictionaries

b= maps

you have to buy 3 dictionaries, so put a 3 next to the a (dictionaries) so that you can multiply them by each other.

a3+b= 60 (the amount of money you have)

we already know the cost of a=15 so replace a with $15

($15 x 3)+b=60

multiply 15 and 3 to get $45 and replace it with $45

45+b=60

and then replace b with 15 to get the total:

45+15=60

that means you have $15 left after buying 3 dictionaries.

15 divided by the cost of a map ($5) equals 3.

so you can buy 3 maps.

sorry if it was confusing!