Answer:
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