10 books cost $30. To figure it out, it's just 3 times the number of books. XD
It cost $5 for his brother's ticket.
Step-by-step explanation:
Let,
Micheal's ticket price= x
His brother ticket price = y
According to given statement;
x+y=12 Eqn 1
y = x-2 Eqn 2
Putting value of y from Eqn 2 in Eqn 1

Dividing both sides by 2;

Putting x=7 in Eqn 2

It cost $5 for his brother's ticket.
Keywords: linear equation, substitution method
Learn more about linear equations at:
#LearnwithBrainly
Both are
indicators of the chemical composition of silicate minerals, magmas and rocks.
Mafic is
used for silicate minerals, magmas and rocks that are composed of heavier
elements, like magnesium, iron, calcium and sodium. They are dark and have high
specific gravities.
<span>Opposite to
the this, felsic silicate minerals, magmas and rocks in their composition have
less from these heavy elements. They are composed from silicon, oxygen,
aluminium and potassium, are light in color and have lower specific gravities.</span>
Let x be this number 10% of the number x is (10%)(x) → 0.1x
Then 10% of a number x, added to that number is (1.1x):
x + 0.1x = x(1+0.1) = x(1.1) = 1.1x