The major portion of weight in satellite launch vehicles is contributed by fuel. Thus, vehicles have to carry a large weight of fuel during their course of journey. Earlier Satellite Launch Vehicles (SLV) used to be of a single stage vehicles. Such SLVs used to be very heavy as well as expensive in terms of its fuel consumption.
To overcome this problem of launch vehicles carrying heavy load during its entire journey, it is provided with more than one stage. In multistage the weight of the vehicle can be reduced step by step, after its launching.
Thus, it saves fuel consumption. Hence, it is beneficial to use a multistage satellite launch vehicle