Daniel rollerbladed 3 miles in 12 minutes. What was his speed in miles per hour? A
12 miles per hour

B
15 miles per hour

C
21 miles per hour

D
40 miles per hour

B

15 Miles per hour

Step-by-step explanation:

Step one: find out how many times 12 goes into 60 (because 12 is the amount of minutes it took to go 3 miles, and one hour is 60 minutes.)

Step two: 12 goes into 60 by five so you have to multiply the three times five as well.(look at step three for more info.)

Step three: 3 miles times 5

12 minutes times 5

equals |

V

15 miles

60 minutes/ 1 hour

step-by-step explanation:

the original amount doesn't ''re just looking for the time it takes for 1/2 of the substance to we have

(1/2) =)     take the ln   of both sides

ln (1/2)   = )   and we can write

ln(1/2) = ) lne     and lne   = 1     so we have

ln(1/2) = -.1092t     divide both sides by -.1092

t = ln(1/2)/-.1092 = about 6.347 days = about 6.3 days (rounded)