Jeffrey is using a copy machine to make posters for a school play. The machine prints the posters at a constant rate. After 3 minutes, he makes 108 posters. How long it will take Jeffrey to make 396 posters? a.10 min B.11 min c.12 min d.9 min

B: 11 minutes.

Step-by-step explanation:

So, we know that the machine prints at a constant rate.

After 3 minutes, the machine prints 108 posters.

So, let’s find the unit rate. We will divide the output over the input. So:

So, the unit rate of the machine is 36 posters per minute.

We can write an equation. If t represent the number of minutes and p represent the amount of posters, then:

Gives the amount of posters p and t minutes.

We want to know how long it will take Jeffrey to make 396 posters.

So, we can substitute 396 for p and solve for t. Hence:

Divide both sides by 36:

Therefore, it will take Jeffrey 11 minutes to make 396 posters.

the largest number of the four options is 1.8 x 10-2

you have it in scientific notation.

1.80 x 10-6   = 0.00000180

1.80 x 10-4   = 0.000180 (bigger, or "less small", than the former one)

so

1.8 x 10-2       = 0.0180. as you see. the "less small", or the biggest one of them all.

as you have negative exponent, it means you are dividing 1.8 by 100 (i.e. moving the dot towards left, two times).

if you had positive exponent for the scientific notation, power of tenths, you would be multiplying times 100 (moving the dot towards right) as below:

1.8 x (10)2 = 180

so. if you have negative exponent in scientific notation, move the dot toward left. if it is positive, toward right as many times the exponent tells you.