Answer:
Step-by-step explanation:
The initial value = 390
It decayed at an exponential rate of 8.5% for 9weeks which is also 63days
Decay exponential rate after 42days will be:
8.5% = 63days
x% = 42days
8.5% ×42days = 63days×x%
357 = 63x
x = 357/63
x = 5.666%
Hence after 42days it would have decayed by 5.666% of it initial value.
That is 5.666% of 390
5.666/100 × 390
0.056×390
= 22.0974
To the nearest hundredth 22.10
Hence the value left will be 390-22.0974
= 367.9026
To the nearest hundredth 367.90
