Every element of the population does have an equal probability of getting chosen in a basic random sampling. The entire population should be included in your sample frame. To conduct this sort of sampling, technologies such as random numbers or other approaches relying completely on chance can be used.
(4/7)÷ (3/-8). Division of fractions is the same as multiplying their reciprocals. So (4/7) x (-8/3). Now multiply the numerators together and denominators together (make sure you only use the negative sign once). (4 x -8) / (7 x 3) = -32/21