Solution: (4)
A = {a1, a2, a3, a4}
B = {b1, b2, b3, b4, b5, b6, b7}
n (A) = 4 and n (B) = 7
Total number of injections = 7P4
= 7! / 3!
= 7 * 6 * 5 * 4
= 840
Solution: (4)
A = {a1, a2, a3, a4}
B = {b1, b2, b3, b4, b5, b6, b7}
n (A) = 4 and n (B) = 7
Total number of injections = 7P4
= 7! / 3!
= 7 * 6 * 5 * 4
= 840