Question

If ³⁰C +2 = ³⁰C – 2, then r equals:
(a) 8 (b) 15
(c) 30
(d) 32​

Answer 1

Answer:

according to formula :

n(r+2) = (r-2)

= 2r = n

= r = 30/2

= r = 15

hence option b