Question

As part of a competition, Diego must spin around in a circle 6 times and then run to a

tree. The time he spends on each spin is represented bys and the time he spends
running is r. He gets to the tree 21 seconds after he starts spinning. If it takes Diego 1.2
seconds to spin around each time, how many seconds did he spend running?

Answer 1

It took him 13.8 sec to run

Explanation:

Time to spin 6 times can be represented mathematically by "6 s". Then the total time it took him to get to the tree (which must be the addition of the time spinning plus the time running) is:

6 s + r = 21 sec

since each spin takes him 1.2 sec, then we have:

6 (1.2 sec) + r = 21 sec

7.2 sec + r = 21 sec

r = 21 sec - 7.2 sec

r = 13.8 sec