Astack of nested paper cups is 8 inches tall . the 1st cup is 4 inches tall and each of the rest of the cups in the stack adds 1/4 of an inch to the height of the stack. how many cups are in the stack? is there a paper cups is 8 inches tall

Planet earth has a mass of 5.9726x10²⁴ kg.then: 5.9726x10²⁴ kg=100% of the total earth mass.if the water´s mass=5x10-4 % of the total mass, we can solve this problem by the rule of three.5.9726x10²⁴ %*10⁻⁴ %x=(5.9726x10²³ kg)(5*10⁻⁴  %) / 100 %=2.9863x10¹⁹ kganswer:   the mass of the planet´s water would be   2.9863 x 10¹⁹ kg.