Question

Arrange the following ratios in descending order, which number will be last?

11:14, 17:21, 5:7, 2:3

1. 17:21
2. 5:7
3. 2:3
4. 11:14

Answer 1

Correct Answer - Option 3 : 2:3

Given:

11:14, 17:21, 5:7, 2:3

Concept used:

Lowest Common Multiple

Calculation:

By writing the ratios in fraction form, we get

11/14, 17/21, 5/7, 2/3 

LCM of denominators of fractions (3, 21, 14, 7) 

⇒ LCM(3, 21, 14, 7) = 42 

By converting the given ratio as equivalent, we get 

11/14 × 3/3 = 33/42 

17/21 × 2/2 = 34/42

5/7 × 6/6 = 30/42 

2/3 × 14/14 = 28/42 

From above, writing the above fractions in descending order, 

34/42, 33/42, 30/42, 28/42

                       or 

17/21, 11/14, 5/7, 2/3 

∴ The last ratio will be 2/3 or 2 : 3.