A swimming pool is 350 decimeter long.how many times must you swim back and forth to go a distance of 800 meters?

A decimetre is 1/10 of a metre so there are 8000 of them in 800 metres. To find out how many lengths need to be swum we need to divide 8000 by 350. That gives 22.86, so the swimmer will have to complete almost 23 lengths to cover 800 metres.