What does SPF stand for, and what is the difference between a SPF 15 and a SPF 30 sunscreen?

SPF: The SPF (Sun Protection Factor) of a sunscreen is a measure of how well it protects the skin from sunburn.

SPF 30 is the most common level for most people and skin types. No sunscreen can block all UV rays, but what we do know is: SPF 15 blocks 93% of UVB rays, SPF 30 blocks 97% of UVB rays and SPF 50 blocks 98% of UVB rays. So, the difference between 30 and 50 is about 1 percent.

step-by-step explanation:

how many centimeters did the level of the salsa go down by?

d

step-by-step explanation:

hello and welcome!

so, when we see the words "proportional" along with a table, we need to know that we're looking numbers that divide by the same thing.

looking at this table, we simply have to do a trial and error, and divide to see which numbers have the same quotient. if you look at choice a & c, they both have equal quotients for three of the numbers, with one exception, so those can't be the answer. looking at b, there is no similarity, so that can't be it. then, we see d; if you divide all the numbers in the table, you'll see that they all divide by two, which is a proportional relationship, and our answer!

also, always remember that the x will always be the number that goes into y, and somewhere behind this table, is a formula. for this specific table, the formula would be:

since our x-value is being divided by two to get the y-value. and if they were to ask for more numbers in the series, this is the formula you would use to find them.