Let x be the number.
Set up an equation:
2x - 2/3x = 20
Simplify:
1 1/3x = 20
Divide both sides by 1 1/3
X = 15
The number is 15
It'll be the opposite reciprocal in front of the X like instead of 3 it will be -1/3 so flip it and change the sign
You would add up the percentages first, which would bring everything up to 35%. You would then take the original cost of the item, which is $30 and multiple it by the 35%.
The equation would look like...
30 x .35 =
This will give you $10.50, which isn't the final answer.
You would then subtract 10.50 from the $30 that was asked for at the beginning by the retailer.
Your final answer is $19.50. :) Which isn't a bad deal if I say so myself.
The sum of the interior angles in the polygon whose side is 10 is 
<h3>What is sum of interior angle of polygon ?</h3>
The sum of the interior angles in a regular polygon is given by the formula 180(n – 2), where n is the number of sides in the polygon.
As, The formula for calculating the sum of interior angles is ( n − 2 ) ×
S0, n=10
Then, sum of interior angle be = (n-2) x 180
= (10-2) x 180
= 8 x 180

Thus, the sum of the interior angles in the polygon is 
Learn more sum of interior angle of polygon here:
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