JAMB - Mathematics (1978 - No. 6)
The number of telephone calls N between two cities A and B varies directly as the population P\(_{A}\), P\(_B\) respectively and inversely as the square of the distance D between A and B. Which of the following equations represents this relation?
N = \(\frac{kp_A}{D^2} + {cp_B}{D^2}\)
N = \(\frac{k P_{A} P_{B} }{D^2}\)
N = \(\frac{kD_AP_D}{B^2}\)
N = \(\frac{kD^2_AP_D}{B}\)
ব্যাখ্যা
\(N \propto P_{A}\); \(N \propto P_{B}\); \(N \propto \frac{1}{D^{2}}\)
\(\therefore N \propto \frac{P_{A} P_{B}}{D^{2}}\)
\(N = \frac{k P_{A} P_{B}}{D^{2}}\)