Kelly already has $9 and will make $18 hour mowing lawns. Write an inequality to represent how many hours ,x, must Kelly work to save at least $72.

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:

if you're trying to figure out how much each ounce cost it would be 0.20

cents each ounce