So an athlete trains on a circular track of radius 40m and jogs 10 laps each day 5 days a week. how far dose he jog each week?

Ok.  he jogs 10 laps in a day and each lap is 40 m so 10 times 40 is 400
he jogs 400 meters in a day then multiply that by 5 for the week
400 times 5 is 2000
he jogs 2000 meters each week

the law of definite proportions states samples of a compound will always contain the same proportion of elements by mass. in other words, a given compound will always contain the same elements in the same proportions by mass.the law of multiple proportions states when two elements combine with each other to form more than one compound, then the weights of one element that combine with a fixed weight of the other are in a ratio of small whole numbers.