Percentages| Ratios | Arithmetic | simplify | Tricky question | Olympiad problems | #maths |#shorts

Class 10 Maths | Chapter 5 | Arithmetic Progression | Important Questions | Quick Revision

Simplest or empirical formula: Ascorbie acid (vitamin C ) a white crystalline solid, that is present in fruits and vegetables, curves scury and may help prevent the common cold. It is composed of 40.92%C, 4.58% H , and 54.50% O by mass. Determine its emprical formula. Strategy: Because one mole of atoms of any given element is 6.022xx10^(23) atoms, the ratio of the numbers of atoms the ratio of the numbers of atoms in any sample fo a compound is the same as the ratio fo motes of atoms is that compound. Thus, the energy is to, find the relative number of moles of each element in the compound and then use the numbers to establish the mole ratio of the elements which in turn give the subsrips in the empral formula. This calculation si carried out as follow: Step 1: Becuase the sum of all the percentages is 100% it is conventient to solve this type of problem by considerinf exactly 100g of the substance, which means 100.00g of ascoric acid contains 40.92g of C, 4.58g of H , and 54.50g of O Next we need to calculate the number of moles of atoms of each element in the compound. Step 2: We then obtain teh simplest whole number ratio between these number that gives that ratio of atoms in the sample and hence, the simplest or empirical formula for the compound.

Shobha’s Mathematics Test had 75 problems i.e, 10 arithmetic, 30 algebra and 35 geometry problems. Although she answered 70% of the arithmetic 40% of the algebra and 60% of the geometry problems correctly she did not pass the test because she got less than 60% of the problems right. How many more questions she would have needed to answer correctly to earn a 60% passing grade?

Shobha's Mathematics test had 75 problems i.e., 10 arithmetic, 30 algebra and 35 geometry problems. Although she answered 70% of the arithmetic, 40% of the algebra and 60% of the geometry problems correctly, she did not pass the test because in algebra she got less than 60% of the problems right. How many more questions she would have needed to answer correctly to score a 60% passing grade?

There are 200 questions on a 3 hour examination. Among these questions are 50 Mathematics problems. It is suggested that twice as much time be spent on each Maths problem as for each other question. How many minutes should be spent on Mathematics problems? (a) 36 (b) 60 (c) 72 (d) 100

Converting Fractional Number To Percentage|Converting Decimals To Percentage|Converting Ratio To Percentage|Converting Percentage To Fractions Or Decimals|Question Practice|Increase Or Decrease As Percent |OMR

Study the following table carefully and answer the questions after analysing the data. In the table the percentage of population below poverty line and ratio of males and females in five districts of a state have been shown. If the total population of district D_(4) is 35000, what is the number of females above poverty line in the district D_(4) ?

Study the following table carefully and answer the questions after analysing the data. In the table the percentage of population below poverty line and ratio of males and females in five districts of a state have been shown. If the total population of district D_(3) is 40000, what is the population below poverty line in the district D_(3) ?

Study the following table carefully and answer the questions after analysing the data. In the table the percentage of population below poverty line and ratio of males and females in five districts of a state have been shown. The total population of the disctrict D_(1) is 30000. The number of females below poverty line in the district D_(1) is