When a number is decreased by 30% of itself, the result is 21. What is the number?

The number is

A tree 24 feet tall casts a shadow 12 feet long. Brad is 6 feet tall. How long is Brads shadow

How do I simplify - 3 (x-4)

Find the possible value or values of n in the quadratic equation 2n2 - 7n + 6 = 0.

Find the sum of the series 14+11+8+5 ... - 82

Evaluate the expressions 12 (8-5)

Which expression is equivalent to 4x-10y

1/3 (22) - 1 - 1/2 (12)

In a fish tank, the ratio of goldfish to guppies is 2 to 4. There are a total of 12 fish in the fish tank. Determine the number of goldfish in the fish tank.

I'm doing easy math but i don't remember learning this so heres the question. One angle of a triangle is 20 degrees. The second angle's measurement is four times the third. Whats is the measure of the third angle?

If I have 10 dollars and I win 6 out of 10 and lose 4 out of 10 and bet 1$ each trade, how much should there be left after 10 trades?