Relations And Functions

We are given the equation

4a%20%3D%205b

, and we are asked to find the number of ordered pairs

(a%2C%20b)

where

a%20%5Cin%20%5C%7B1%2C%202%2C%203%2C%20%5Cdots%2C%2030%5C%7D

and

b

is determined by this equation. We can solve for

b

in terms of

a

b%20%3D%20%5Cfrac%7B4a%7D%7B5%7D

For

b

to be an integer,

a

must be a multiple of 5. Therefore, the possible values of

a

are

a%20%3D%205%2C%2010%2C%2015%2C%2020%2C%2025%2C%2030

, and for each of these values of

a

, we get a corresponding value of

b

. Thus, there are 6 such pairs

(a%2C%20b)

. Therefore, the correct answer is 6.

Chapter Questions
1 MCQs