Question 481982
At 1 hour from 1:10, the blue line bus has made it's 3rd stop
At Helen's stop, since {{{ 20 + 20 + 20 = 60 }}}
At 1 hour from 1:10, the red line bus has made it's 2nd stop
At her stop, since {{{ 30 + 30 = 60 }}}
So 1:10 + 1 = 2:10 is the next time that Helen can get off 1 bus
and get on the other one