this is a funny one. teachers do this to try to confuse you with the numbers. first you need to find out what is important in the question.
2 mammoths, 7 hours, 11 kilometers.
&
5 mammoths, ? hours, 22kilometers.
the amount of mammoths do not matter, because each walk the same speed.
so you only need to look at this.
7 hours to go 11 kilometers
&
? hours to go 22 kilometers
fast answer is. it's twice the distance so it will take twice as long. 14 hours.
solve answer.
7×60min = 420min
420min ÷ 11 kilometers = 38.18181818min per 1 kilometer.
38.18181818 • 22 = 839.999999min round up 840.
840min ÷ 60min = 14 hours