1
x/16=5/4⇒x=(16×5):4=
⇒x=20
2.
15/100=3/20 se simplifica prin 5
3.
1,2/x=y/1,25
10xy-2³=?
1,2/x=y/1,25⇒produsul mezilor=produsul extremelor
x×y=1,2×1,25
x×y=1,5
atunci
10xy-2³=? va fi
x×y=1,5 deci
xy=10×1,5=15
2³=8
deci 10xy-2³=15-8
10xy-2³=7
4.
10 % din 300
= (10/100)×300
= 3000/100
= 30 lei
Telefonul costa acum 300 + 30 = 330 lei
5.
a) 250 ml×85/100
simplificam cu 50 ⇒
(5×85)/2=425/2
=212.5 ml suc
b) 250 ml - 212.5 ml
= 37,5 ml apa
c) 100% - 85% =
= 15% (apa)
