8. Number of boys in a class is twice the number of girls. 20% of the girls are brunettes and of the rest – half are blondes: Mary, Clara, Gina and Trisha. How many boys study in this class?

20 boys

Step-by-step explanation:

b = 2g

100% - 20% = 80%

80% ÷ 2 = 40% = 0.4

0.4g = 4 ⇒ g = 4 ÷ 0.4 = 10

b = 2 × 10 = 20

There are 10girls and 20 boys study in the class.

step-by-step explanation:

i hate black

$5.41

step-by-step explanation:

$20 - $14.51 = $5.49.