Are SPF's in sunscreen and makeup additive in protection? ie sunscren 30+ base 10 + powder 10 = SPF50?

Question

Are SPF's in sunscreen and makeup additive in protection? ie sunscren 30+ base 10 + powder 10 = SPF50?

Answer 1

I dont think so.

the SPF number refers to how long you can be in the sun without burning

for example, if you normally burn after 30 minutes of exposure and use an SPF 10 (30minutes x 10spf = 300 minutes) you could be in the sun for 300 minutes without burning.

so i think after an amount of time the lower SPFs would stop working and the highest SPF will still be functioning as it would if there were no others.

I'm not 100% sure on this, I don't remember where I heard it.