On the island, 75% of men are married, 80% of women are married, and how many are married? Bashny.Net

The child in the fifth and sixth grades must understand. How to solve problems with percentages. He will have to deal with them in adulthood. And this knowledge and skills will be useful not only when working with bank deposits, loans or mortgages.

Even in everyday affairs, a person deals with discounts in supermarkets, with taxes, with the nutrient content of food. Failure to make such calculations quickly complicates things.

And today's edition. "Site" Ask readers to check how well they work with percentages. Try to solve a few school problems. Will you be able to do it easily or make childish mistakes? Do not forget to check our answers in the second part of the article.



How to solve problems with percentages

1. The first problem seems cumbersome, but it will not be difficult for a diligent student to solve it. From the conditions we understand that some experimenters mixed equal volumes of 21 percent and 95 percent solution. And you need to figure out what solution eventually turned out, what concentration here.
   View this post on Instagram
   
   Publication by Mathematics Repetitor | UGE, OGE (@math_u.an)
   
   
   
   
2. The second task is harder. Here you need to understand what the weight of cucumbers will be after the percentage of moisture in them decreases from 99% to 98%. Although we know that initially the weight of these vegetables was exactly 100 kilograms.
   View this post on Instagram
   
   Publication by Tatyana Vasilievna (@razvitie_v_ddt)
   
   
   
   
3. The last problem today is about an island where 75% of men are married and 80% of women are married. It is necessary to calculate how many percent of the islanders (both men and women) are married. Can you find that number?
   
   
   
   

Tips and solutions

1. Since the volumes of the two solutions are equal, when mixing we get twice as much solution as it was separately. But what will be the concentration here? You just need to perform the actions: (21 + 95) ÷ 2 = 116 ÷ 2 = 58. Therefore, the resulting solution will be 58 percent.
   
   
   
   
2. If 100 kg of cucumbers is 99% water, then 100 × 0.99 = 99 kg of water. Then all the rest in the cucumbers remained 100 - 99 = 1 kg. If the humidity of cucumbers decreased from 99% to 98%, the share of dry matter increased from 1% to 2%. And the weight remained 1 kg. If 1 kg equals 2% or 0.02, then the new weight of cucumbers is now 1 ÷ 0.02 = 1 × 50 = 50 kg. Surprisingly, the humidity decreased by only 1%, and the total mass decreased by half.
   
   
3. Since the number of married men and women is the same, the answer is still possible. Therefore (75 + 80) ÷ 2 = 155 ÷ 2 = 77.5%. So many islanders are married. Or did you get a different answer?
   
   
   
   

Be sure to share your thoughts and answers in the comments. We may have made a mistake in our calculations somewhere. And your help will be very useful, so that the truth will prevail.

Also solve our recent school puzzles. And try to find the key to cunning examples that any adult can baffle.