To boor everyone with math. SPF is supposedly the inverse of having not sunscreen. Lying in the sun for an hour with SPF 15 is like 1/15 of an hour with no sunscreen and SPF 30 is like 1/30 of an hour with no sunscreen. So and hour at SPF 15 and an hour with SPF 30 is like1/15 + 1/30 = 3/30 = 2/20 or two hours with SPF 20 sunscreen.
Yakety Sax almost 6 years ago
Sunscreen, in the world of beauty, is the ultimate in adulting. Emily Weiss
I don’t wear sunscreen. I don’t have a skincare program. Pamela Anderson
1MadHat Premium Member almost 6 years ago
What if it subtracts, and it comes out to -15? 8^)
Alberta Oil Premium Member almost 6 years ago
It depends.. it adds up if you are by yourself.. and subtracts if you have a special friend to rub it on…
whelan_jj almost 6 years ago
To boor everyone with math. SPF is supposedly the inverse of having not sunscreen. Lying in the sun for an hour with SPF 15 is like 1/15 of an hour with no sunscreen and SPF 30 is like 1/30 of an hour with no sunscreen. So and hour at SPF 15 and an hour with SPF 30 is like1/15 + 1/30 = 3/30 = 2/20 or two hours with SPF 20 sunscreen.