Verified Solution • 2025–26 Session
moderate
QJEEM21Mac3a7: JEE Main 2021 Mathematics - Class 11 JEEM21Mac3a7 Solution: Let A = {2, 3, 4, 5, ....., 30} and ' ' be an equivalence…
Let A = {2, 3, 4, 5, ....., 30} and ' ' be an equivalence relation on A A, defined by (a, b) (c, d), if and only if ad = bc. Then the number of ordered pairs which satisfy this equivalence relation with ordered pair (4, 3) is equal to :
Multiple Choice Options
- A 5
- B 6
- C 8
- D 7
Step-by-Step Verified Solution
ad = bc
(a, b) R (4, 3) 3a = 4b
a = b
b must be multiple of 3
b = {3, 6, 9 ..... 30}
(a, b) = {(4, 3), (8, 16), (12, 9), (16, 12), (20, 15), (24, 18), (28, 21)}
7 ordered pair
(a, b) R (4, 3) 3a = 4b
a = b
b must be multiple of 3
b = {3, 6, 9 ..... 30}
(a, b) = {(4, 3), (8, 16), (12, 9), (16, 12), (20, 15), (24, 18), (28, 21)}
7 ordered pair