A radioactive substance decays over time. Its mass decreases by 12% each year.
If it has a mass of 420g this year, what will its mass be in 7 years?
Give your answer to 2 decimal places.

30 miles

step-by-step explanation:

we know that 60 seconds equals 1 minute and 60 minutes 1 hour

44 ft       60 sec     60 min     158400   ft

  *   *   =

1 sec       1 min       1 hour         hour

we know that there are 5280 ft per mile

158400   ft       1 mile         30 miles

  *   =

1   hour               5280 ft     1 hour

so in 1 hour   it can travel 30 miles

1/8 3/16 3/4

step-by-step explanation:

you put them as all the same denominator and multiply

the answer is a if my teacher taught me correct