Easy way to solve this half life problem?

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super112

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If 88% of a pure sample decays in 24 hours, what is the half life?

Destroyer is having me set up a table and work backwards but to be honest I do better seeing it mathematically. I tried my best to set up a ratio knowing that 12g of sample exist at 24 hr mark but so far to no avail. Is a formula possible for this questions?

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If 88% decays in 24 hours then that means 88g of a 100g sample will decay in 24 hours leaving 12% of the original.

Start: 100 g
1 HL: 50 g
2 HL: 25 g
3 HL: 12.5 g remains

24 hours: 12 g left (100-88)

3 half lives mean in a span of 24 hours it decays every 8 hours

Is this not the case?
 
Yup, actually it's much easier to see now in terms of HL rather than hours. Thannks!
 
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