几道英文数学题请教急
请帮我写出公式
1.aspacecraftcountdownisat-8second.inhowmanysecondswillthespacecraftbe15secondintoitsflight.
2.themelvillessellrecordsatafleamarketeverysaturday.on4saturdayinjune,theyhadaprofitof$30,lost$20,lost$40,andhadaprofitof$60.howmuchwastheirprofitorlossinjune