What single percentage change is equivalent to a 11% decrease followed by a 13% decrease

24%

Step-by-step explanation:

x-(11/100)x

89/100x

followed by

89/100x-13/100x

76/100x

so the total decrease is calculated as

x-76/100x

(24/100)x

i.e 24% decrease

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