If 39 is 3/5 of all the people then you can divide it by 3 (=13) and multiply is by 5 (= 65)
Answer: There are 65 people in the club.
Now we have a negative exponent, which is the opposite of a positive exponent.
If a positive exponent means you're multiplying by 10s and it makes a number bigger by moving the decimal to the right, then
the opposite of this is that a negative exponent means you're dividing by 10s and making the number smaller by moving the decimal point to the left.
Examples:


The trick is to recognize that
is the same thing as 
and
mean the same thing.
So, 
For your exercise,
means you'll move the decimal point 24 places to the left, to make the number smaller.
The first step would be to subtract 1 from both sides, leaving you with 5x = 10.
Answer:
The formula to find the perimeter of a rectangle is 2L + 2W.
Here L=5 and W=2; hence:
2*5+2*2
=14
The perimeter is 14.
The formula to find the area of a rectangle is length × width; hence:
5*2=10
The area of the rectangle is 10.
Answer: TANK B, because it has the greatest volume
For any confused individuals from edge
Mateo has two fish tanks that have different volumes. He wants to use the tank that can hold the greatest amount of water. Which tank should he use, and why?
Mateo should use Tank B, because it has the greatest volume