Everything is learned in comparison. The relation of some sizes to each other can be expressed as a percentage. For example, having counted what percent of liquid from bulk contains in 1 kg of tomatoes and cucumbers, you learn, what will be more juicy.
It is required to you
- 1) Paper
- 2) Handle
- 3) Calculator
Instruction
1. Definition protsentasoglasno of the Big Soviet encyclopedia, percent are the 100-th shares whole (taken as an unit). Percent call the one 100-th share and designate by the sign of %.
2. An experiment with yablokomdlya take presentation the whole apple - it is unit, or 100%. Cut it in half, give a half to the friend. Now at you 1/2 or 0.5 or 50% (100%/2) of apple. Again cut and give a half to the friend. Now at you 1/4 or 0.25 or 25% of apple. And now cut this part of apple on 25 parts, distribute 24 parts to friends. Remained with you (1/4)/25 = 1/100 or 0.25/25 = 0.01, or 25%/25 = 1% of apple.
3. The percent from a chislasoty share from number means that 1% of number, for example, 36 is equal 1/100 parts or 0.01 shares from number of 36.36*1% = 36*1/100 = 36*0.01 = 0.3636*6% = 36*6/100 = 36*0.06 = 2.161% of 36 is equal to 0.36; 6% from 36 it is equal to 2.16
4. We make proportsiyupr the solution of tasks with percent for descriptive reasons or checks of result it is useful to make a proportion. For example, at the beginning of a year of pear cost 63 rubles/kg. Inflation in a year was 11.2%. How many will cost pears in the end of the year? It is important to determine correctly the sum which is accepted to 100%. Usually it is the initial sum concerning which there is a growth or reduction.63 of ruble/kg - it is 100%. In the end of the year the price will be 100%+11.2% = 111.2% or 1.112 shares from 63 ruble/kgsostavta a proportion: 63 rubles/kg – 100%X ruble/kg – 111.2% where X (X) is unknown, i.e. how many will cost pears in the end of the year. Apply the rule of a proportion: (63 rubles/kg) / (X ruble/kg) = 100% / 111.2%Отсюда find X:(63 rubles / kg*111.2% of)/100% = 70.1 rubles/kgprotsenta as unit of measure at the same time are reduced.
5. The advantage edited proportsiiusvoiv the rule of a proportion, you can solve the return problems when sizes are set and it is required to find percent. For example, the annual salary of Sergey last year was 210 thousand rubles, in flowing – 290 thousand rubles. By how many percent did its salary increase in comparison with previous year? 210 thousand rubles – 100%290 thousand rubles – H%Naydite X:(of 290 thousand rubles of *100% of)/210 thousand rubles = 138%B the current year Sergey's salary was 138% or 1.38 shares of 210 thousand rubles i.e. grew by 38% of rather last year.
6. Percent from number with the help to a proportsiinaydita of 18% of the sum 189 – for this purpose make a proportion.189 - it is 100% of X is 18% (189*18% of)/100% = 34.02.