A stationary source emits sound waves of frequency 500 Hz. Two observers moving along a line passing through the source detect sound to be of frequencies 480 Hz and 530 Hz. Their respective speeds are, in $\mathrm { m } \mathrm {~s} ^ { - 1 }$,\\
(Given speed of sound $= 300 \mathrm {~m} / \mathrm { s }$)\\
(1) 16, 14\\
(2) 12, 16\\
(3) 12, 18\\
(4) 8, 18