Question

1) Calcule:

a) 10 % de 640 =

b) 20 % de 500 =

c) 35% de 450 =

d) 25% de 1200 =

e) 86% de 420=​

Answer 1

1) Fórmula: %/100 = x/Todo

a) 10/100 = x/640

10 × 640 = 100x

6400 = 100x

x = 6400/100 = 64

b) 20/100 = x/500

20 × 500 = 100x

10000 = 100x

x = 10000/100 = 100

c) 35/100 = x/450

35 × 450 = 100x

15750 = 100x

x = 15750/100 = 157,5

d) 25/100 = x/1200

25 × 1200 = 100x

30000 = 100x

x = 30000/100 = 300

e) 86/100 = x/420

86 × 420 = 100x

36120 = 100x

x = 36120/100 = 361,2