If Steve paid back $7,945 on a $7000 simple interest loan after 3 years. What was the interest rate?
1 answer:
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The Researcher will find 69 viruses, because 231 viruses are decayed in 7 hours, if a virus with a decay rate of 19% per hour and they start with 300 viruses.
Step-by-step explanation:
The given is,
A new virus with a decay rate of 19% per hour
They start with 300 viruses
Step:1
Formula to calculate the viruses at decay rate,
............................(1)
Where, y - No of viruses after given time
A - Viruses at initial stage
r - Decay rate
t - No. of hours
From the given,
A = 300
r = 19% per hour
t = 7 hours
Equation (1) becomes,
Viruses of 7 hours ≅ 69 viruses
( or )
Step:1
For 1st hour,
= (No.of viruses in hour) - (No,of viruses in last hour × Decay rate )
= (300)-(300 × 0.19)
= 300 - 57
= 243
For 2nd hour,
= (243)-(243 × 0.19)
= 243 - 46.17
= 196.83
For 3rd hour,
= (196.83)-(196.83 × 0.19)
= 196.83 - 37.39
= 159.4323
For 4th hour,
= (159.4323)-(159.4323 × 0.19)
= 159.4323 - 30.2921
= 129.1402
For 5th hour,
= (129.1402)-(129.1402 × 0.19)
= 129.1402 - 24.5366
= 104.6035
For 6th hour,
= ( 104.6035)-( 104.6035 × 0.19)
= 104.6035 - 19.8747
= 84.7288
For 7th hour,
= (84.7288)-(84.7288 × 0.19)
= 84.7288 - 16.0984
= 68.63 viruses
Result:
The Researcher will find 69 viruses, because 231 viruses are decayed in 7 hours, if a virus with a decay rate of 19% per hour and they start with 300 viruses.