<span>When price falls quantity demanded will rise, but for simplicity economists take the absolute value of the elasticity number.</span>
Answer
Together, they have 99 marbles.
Explanation
Ravi has 33 marbles.
His brother has twice (two times) as many marbles as him. Ravi's brother has 33×2=66 marbles.
Together, they have 33+66=99 marbles.

The left sides of the equations are the same and the right sides of the equations are different, therefore the system of equations is inconsistent.
Answer: B. inconsistent.
√
6
⋅
√
15
=
3
√
10
Explanation: By radical laws,
√
a
⋅
√
b
=
√
a
b
.
Using this law:
√6⋅√15
=√90
√90 has 9, a perfect square, as one of its factors, so it can be simplified.
√90
=√9⋅10
=√9⋅√10
=3√10