Austin takes 1 quart of water on his hike. He drinks one third of the water going up the trail. He drinks one forth of water when he stops for lunch. how much does he have left

We need to find that he is taking 1/4 of that water with him ... he then drinks 1/3 on the way up ... how much does he have now? well what is left of that 1/4? now we have 2/3 of 1/4 left ... to find that #, we need to do some multiplication ... so:

2/3 x 1/4 going by cross simplification. we no have:

1/3 x 1/2 because i divided the numerator 2 and the denominator 4 by 2 ... as it an easy multiple.

so now we have 1/6. all Austin has let for his return back is one sixth of a gallon of water