Janell ran a race 11.4 seconds faster than Hilda. Hilda ran the race 7.2 seconds slower than Gracie. If the average (mean) of their three times was 62.6 seconds, how long did it take each girl to run this race?

X= Gracie

X+7.2=Hilda

X+7.2-11.4=Janell

(X+X+X+7.2+7.2-11.4)÷3=62.6

(3x+3)÷3=62.6

3X+3=187.8 (I arrive at 187.8 because I multiple 62.6 by 3)

3X=187.8-3

3X=184.8

3X/3=184.8/3

X=61.6

Step-by-step explanation:

GRACIE X=61.6

Hilda X+7.2=61.6+7.2=68.8

Janell X+7.2-11.4=61.6+7.2-11.4= 57.4

step-by-step explanation:

try remembering the steps

explanation:

infrared radiation has wavelength in the range between 700 nm and 1 mm. lets' convert these values into scientific notation, keeping in mind that:

let's start from the lower value, we have:

(we moved the dot two places to the left, so we increased the exponent by 2 units, from -9 to -7)

the higher value is:

so, the range of wavelength of infrared radiation is: