Using this observation, mentally calculate how much 15% of the values in the table would be. Class 8

Using this observation, mentally calculate how much 15% of the values in the table would be. Class 8

Question 1.

Using this observation, mentally calculate how much 15% of the values in the table would be. Class 8

Solution:

15% of 100 = 15; 15% of 200 = 30;

15% of 50 = 7[latex]\frac{1}{2}[/latex]; 15% of 80 = 12;

15% of 10 = 1[latex]\frac{1}{2}[/latex]; 15% of 35 = 5[latex]\frac{1}{4}[/latex] and

15% of 287 = 43[latex]\frac{1}{20}[/latex].

Question 2.

Suppose you have to mentally calculate the following percentages of some value : 75%, 90%, 70%, 55%. How would you do it? Discuss. Class 8

Solution:

75% of x = [latex]\frac{75}{100}[/latex] × x = [latex]\frac{50}{100}[/latex] × x + [latex]\frac{25}{100}[/latex] × x;

90% of x = [latex]\frac{90}{100}[/latex] × x = [latex]\frac{50}{100}[/latex] × x + [latex]\frac{40}{100}[/latex] × x;

70% of x = [latex]\frac{70}{100}[/latex] × x = [latex]\frac{50}{100}[/latex] × x + [latex]\frac{20}{100}[/latex] × x ;

55% of x = [latex]\frac{55}{100}[/latex] × x = [latex]\frac{50}{100}[/latex] × x + [latex]\frac{5}{100}[/latex] × x;

Note : Do as directed.