For percent it is necessary to face tasks not only to the school student. As a rule, numerical expression of a certain number of percent or how many percent are made by any given number is required or to find in school tasks. Successfully to cope with similar tasks, it is necessary to understand first of all that the percent is a hundredth part something whole. For example, the sum of several numbers can be this whole.
It is required to you
- - the numbers making the sum;
- - any computing device;
- - sheet of paper;
- - pencil or handle.
Instruction
1. Let's say under the terms of a task it is required to find what percent from the sum makes each of composed. Designate numbers which need to be put by any letters. For example, let it will be numbers a, b and c, and their sum equals d. Then the sum of d which in scientific literature is usually designated as ∑ will be equal and +b+c.
2. Find one percent from the sum. For this purpose it is necessary to divide number d into 100. Now you need to find what percent from total makes each of composed. That is you need to learn consistently how many times in numbers a, b and c "keep within" numerical value of 1%. For this purpose divide each of composed into this value.
3. It is convenient to solve such problems with the help of proportions. Take number d for 100%, and necessary to you composed — for x. The % d=100 proportion, and = will turn out x. Remember how to work out the equation with such conditions. Unknown size is by multiplication of number and by 100% and divisions of the received work by d sum It can be expressed the equation x =a*100/d.
4. In precisely the same way it is possible to solve a problem where the sum and how many percent from it are known makes each of composed. In this case as unknown designate number, and the proportion will look as follows: % d=100, x =35%. Work out the equation in the form of fraction in which numerator there will be a work of number d and 35%, and in a denominator — 100%, that is in this case x =d*35/100.