Pātīganita, a book written by Sridharacharya in the 9th century CE, mentions this problem: Class 7

Pātīganita, a book written by Sridharacharya in the 9th century CE, mentions this problem: Class 7

Question 1.

Pātīganita, a book written by Sridharacharya in the 9th century CE, mentions this problem: "Friend, after thinking, what sum will be obtained by adding together and 1 ÷ [latex]\frac {1}{6}[/latex], 1 ÷ [latex]\frac {1}{10}[/latex], 1 ÷ [latex]\frac {1}{13}[/latex], 1 ÷ [latex]\frac {1}{9}[/latex], and 1 ÷ [latex]\frac {1}{2}[/latex]". What should the friend say? Class 7

Solution:

1 ÷ [latex]\frac {1}{6}[/latex] = 1 × [latex]\frac {6}{1}[/latex] = 6,

1 ÷ [latex]\frac {1}{10}[/latex] = 1 × [latex]\frac {10}{1}[/latex] = 10,

1 ÷ [latex]\frac {1}{13}[/latex] = 1 × [latex]\frac {13}{1}[/latex] = 13,

1 ÷ [latex]\frac {1}{9}[/latex] = 1 × [latex]\frac {9}{1}[/latex] = 9, and

1 ÷ [latex]\frac {1}{2}[/latex] = 1 × [latex]\frac {2}{1}[/latex] = 2.

The sum of the above

= 6 + 10 +13 +9 + 2 = 40.

So, the friend should say 40 to Sridhara- charya.

Question 2.

Mira is reading a novel that has 400 pages. She read [latex]\frac {1}{5}[/latex] of the pages yesterday and [latex]\frac {3}{10}[/latex] of the pages today. How many more pages does she need to read to finish the novel? Class 7

Solution:

Pages read yesterday

= [latex]\frac {1}{5}[/latex] of 400 = [latex]\frac {1}{5}[/latex] × 400 = 80 ........... (1)

Pages read today

= [latex]\frac {3}{10}[/latex] of 400 = [latex]\frac {3}{10}[/latex] × 400

= 3 × 40 = 120 ............... (2)

Total pages read = 80 + 120 = 200.

So, to finish the novel Mira need to read (400 - 200) = 200 pages more.