13 ) b)25 %din y =25y/100=y/4
y/4=17=>y=4×17 = 68
c)40%din z =40z/100=2z/5
2z/5=25=>2z=125=>z=125/2
d)60%din i =60i/100=3i/5
3i /5=12=>3i=60=>i=20
e)80%din p =80p/100=4p/5
4p/5=45=>4p =225=>p=225/4
14)
a)p/100×120=36
120p/100=36
6p/5=36
6p =180
p=30
b)p/100×1000=50
1000p/100=50
10p=50
p=5
