A school kitchen is offered a new stove that burns 0.9 kilos of gas an hour, against the 1.4 kilos an hour burnt by the stove now in use. The cook argues that the new stove would cut the gas used in preparing the midday meal. Which of the following is an assumption the cook's argument depends on?

Gas for each hour and gas for each meal are joined only by the hours the stove must run, and a weaker flame may well need more of them. A stove burning 0.9 kilos an hour for two and a half hours uses more than one burning 1.4 kilos an hour for ninety minutes. The price of gas, where the stove stands and the variety of the menu leave that step from a rate to a total unsupported.