One ratio is 30:40 since 15 times 2 is 30 and 20 times 2 is 40.
Remember that percent means parts out of 100 so
x%=x/100
the easier way is to convert fractions to percent by making the bottom number 100 so
4/5 times 20/20=80/100=80%
so the equation is really
-80%-137.5%-20%=-237.5%
In mathematics, an empty set is a unique set having no elements inside it. Its size (which is based on the number of elements inside it) is also zero.
The empty set is sometimes called a null set as well.
Empty set is given the notation of o with a diagonal line through it as shown in the attached picture.