charlie has a $30 smoothie gift card. each time he uses the card to buy a smoothie, $2 is deducted from his card. if the balance on his card today is $12 how many smoothies has he purchased with the card?

9 smoothies

Step-by-step explanation:

$30 - $12 = $18

$18 divided by $2 (per smoothie) is 9, so 9 smoothies!

answer: c.  

step-by-step explanation:

mixtures containing substances that get attracted to magnet can be separated using a magnet. we can separate iron from a mixture of sand and iron, as only iron attracts to the magnet.

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: