Question

a) 25% de..... = 20
b)...... % de 120 = 18

Answer 1

A)  144
B) 

25/100.x=20
25x/100=20
25x=100.20
25x=2000
x=2000/25
x=80

C) 

x/100.120=18
120x/100=18
120x=18.100
120x=1800
x=1800/120
x=15 
X=15% 

Answer 2

Olá,

Resolução :

a) 40% de 360 = ______

Regra de 3

360 --- 100%
   x  --- 40%

100x = 360 . 40

100x = 14400

x = 14400/100

x = 144

R : 40% de 360 = 144

b) 25% de _____ = 20

Regra de 3 :

x ---- 100%
20 ---- 25% 

25x = 100.20

25x = 2000

x = 2000/25

x = 80

R : 25% de 80 = 20

c) ___% de 120 = 18

Regra de 3 :

120 ---- 100%
 18  ---- x%

120x = 100 . 18

120x = 1800

x = 1800/120

x = 15

R : 15% de 120 = 18

Bons Estudos!!