Comparing \(\frac { 1 }{ 4 } \)th of an inch and \(\frac { 3 }{ 8 } \)th of an inch.
\(\frac { 1 }{ 4 } =\frac { 2 }{ 8 } <\frac { 3 }{ 8 } \)
\(\therefore\) Second plant grew more.

\(\frac { Oranges\ not\ eaten }{ Total\ oranges } =\frac { 10-4 }{ 10 } \)
\(=\frac { 6 }{ 10 } \)

No, he is not correct because of the total of 6 triangles 4 are blue.
ie \(\frac { 4 }{ 6 } \)^th triangles are blue.

\(\frac { 8 }{ 5 } =\frac { 5\times 10 }{ 8\times 10 } =\frac { 50 }{ 80 } \)
\(\frac { 1 }{ 10 } =\frac { 1\times 8 }{ 10\times 8 } =\frac { 8 }{ 80 } \)
Here \(\frac { 50 }{ 80 } >\frac { 8 }{ 80 } \)  
\(\therefore \frac { 5 }{ 8 } >\frac { 1 }{ 10 } \)

Product of extremes = 6 \(\times\) 15 = 90
\(\therefore\) Product of means = 90 = 1 \(\times\) 90
The required sets are 1 and 30, 2 and 45, 3 and 30, 5 and 18, 6 and 15, 9 and 10
= 1 \(\times\) 90
= 2 \(\times\)45
= 3 \(\times\) 30
= 5 \(\times\) 18
= 6 \(\times\) 15
= 9 \(\times\) 10
So, 6 : 1 : : 90 : 15.

Distance covered in 1 hr ie., 60 minutes = 6 km
Distance covered in 1 minutes = \(\frac { 6 }{ 10 } \)km
Distance covered in 20 minutes = \(\frac { 6 }{ 60 } \) \(\times\) 20 = 2 km
∴ Cholan cover 2 km in 20 minutes.

Pages read in 2 hours = 20
Then pages read in 1 hour = \(\frac { 20 }{ 2 } \) = 10 pages
∴ pages will be read in 8 hours = 8 \(\times\) 10
= 80 pages.
Number of pages will be read in 8 hrs = 80 pages.

5:4
\(\frac{5}{4}\times\frac{2}{2}=\frac{10}{8}=10:8\)
\(\frac{5}{4}\times\frac{3}{3}=\frac{15}{12}=15:12\)
Equivalent ratios of 5 : 4 are 10 : 8 and 15 : 12

1:6
Equivalent Ratios of 1: 6 are
\(\frac{1}{6}\times\frac{2}{2}=\frac{2}{12}=2:12\)
\(\frac{1}{6}\times\frac{3}{3}=\frac{3}{18}=3:18\)
2 : 12 and 3 : 18 are equivalent to 1 : 6

3:2
\(\frac{3}{2}\times\frac{2}{2}=\frac{6}{4}=6:4\)
\(\frac{3}{2}\times\frac{3}{3}=\frac{9}{6}=9:6\)
6 : 4 and 9 : 6 are equivalent to 3 : 2

Step 1: Express the quantity in the same unit. (Hint : 1 Hour = 60 minutes)
Step 2: Now, the ratio of 40 minutes to 60 minutes is 40:60 \(\Rightarrow {40\over 60}={40\div 20\over 60\div 20}={2\over 3}=2:3\)
This is the ratio in the simplest form.
20 \(\times\) 1 = 20
20 \(\times\) 2 = 40
20 \(\times\) 3 = 60
1 hour = 60 minutes

7 : 15
Fraction = \(​​\frac {7 \div 1}{15 \div 1}=\frac{7}{15}\)
Simplest form = 7 : 15

32 : 24
Fraction = \(\frac { 32 }{ 24 } =\frac { 32\div 8 }{ 24\div 8 } =\frac { 4 }{ 3 } \)
Simplest form = 4 : 3 

15 : 20 
Fraction = \(\frac { 15 }{ 20 } =\frac { 15\div 5 }{ 20\div 5 } =\frac { 3 }{ 4 } \)
Simplest form = 3 : 4