Question

Brainliest will be given! Please help!

Answer 1

Use this formula to find it
$amount \: left = starting \: amount \: {( \frac{1}{2})}^{ \frac{time \: gone}{half \: life} }$
Starting amount = 40g
Half life = 4 days
Time gone = 12 days
Amount left = 40 (1/2)^12/4
= 40 (1/2)^3
= 40 (1/8)
= 5 grams