Sonya can walk 6 kilometers in 3 hours. If she had to walk 10 kilometers how much time will it take her?

Well ... if 6 kilometers equals 3 hours, 10 kilometers would equal her 5 hours.

Because, 6k equals 3 hours, another 6k would equal 6 hours. So what I did was,

that, every 2 kilometers equaled a hour so do that up to tan its 5 hours