During a marathon race an athlete loses 2 % of his mass. At the end of the race his mass is 67.13 kg.
Calculate his mass before the race.

his mass before the race was 68.5kg

Step-by-step explanation:

let,his mass before the race was 'x'

By question,

x-2% of x =67.13

or,x- 2x/100=67.13

or, 98x/100=67.13

or,98x=67.13×100

or,98x=6713

or,x=6713÷98

or,x=68.5

thus,his mass before the race was 68.5 kg

4a. is 3 miles every hour

4b. is 1/3 of an hour per mile

step-by-step explanation:

i dont understand the question? ?

step-by-step explanation: