81511.Find three different prime numbersa,b,cso that their suma+b+c
and their productabcboth end in the digit 7.
12.Karen ran a 42 kilometer marathon in 3 hours, 49 minutes. She did
this by running for 10 minutes, walking for 2 minutes, then running
for 10 minutes, walking for 2 minutes, and so on until she crossed
the finish line. She runs twice as fast as she walks. What is her
average speed, in kilometers per hour, while running?