[please help]
Peter is conducting a chemical experiment in a controlled environment. The initial temperature of the chemical solution was 20°C. The temperature of the solution was 1.5 times the initial temperature after 3 minutes. The temperature of the solution continued to increase at this rate. This situation is graphed below.

Let x represent the number of minutes passed after the start of the experiment, and let f(x) represent the temperature of the solution.

Once the temperature reached 45°C, the experiment was stopped. Over which interval did Peter conduct the experiment?

  B.  0 ≤ x ≤ 6

Step-by-step explanation:

The horizontal grid lines are 10 °C apart, so 45 °C corresponds to a vertical position halfway between the 4th grid line and the one marked 50.

The graph intersects that position at the 2nd vertical grid line. The vertical grid lines are 3 minutes apart, so the 2nd grid line represents 6 minutes.

If Peter conducted the experiment from its start until the temperature reached 45 °C, he conducted it over a period of 0 to 6 minutes, inclusive:

  0 ≤ x ≤ 6

15: 24

62.5%

step-by-step explanation:

this is a direct variation proportion. y = kx

y is the total amount due, k is the constant of variation, and x is the number of texts sent.

plug in the 3.20 and the 16 to solve for the "k". this is the constant of proportionality. it is the value that will not change.

3.20 = k(16). solving you get $.20 per text.

the equation would then be y = .20x