Răspuns :
20/100 = (7,5+m)/(75+m)
1/5= (7,5+m)/(75+m)
75+m=37,5+5m
4m=37,5
m=9,375
1/5= (7,5+m)/(75+m)
75+m=37,5+5m
4m=37,5
m=9,375
_20_ = _7,5+ m_
100 75+ m
20·(75+ m)= 100·(7,5+ m)
1 500+ 20m= 750+ 100m
1 500- 750= 100m- 20m
750= 80m I :10
75= 8m
_75_= m
8
9,375= m
100 75+ m
20·(75+ m)= 100·(7,5+ m)
1 500+ 20m= 750+ 100m
1 500- 750= 100m- 20m
750= 80m I :10
75= 8m
_75_= m
8
9,375= m