The total mass of a box and 3 similar tennis balls is 1.02kg. When the number of tennis balls in the box is tripled, the total mass becomes 2.16kg. Find the mass of the empty box. Give your answer in kilograms.

The total mass of a box and 3 similar tennis balls = 1.02 kilograms.

when the number of tennis balls in the box is tripled the mass becomes = 2.16 kg.

Let’s find the mass of the empty box.

=> there are 3 balls, then it was tripled

=> 3 * 3 = 9

a total of 9 balls

=> 2.16 kg - 1.02 kg

=> 1.14 let’s divide this with 6 tennis balls

=> 0.19 (weight of each tennis balls)

=> 0.19 * 3 = 0.57

=> 1.02 - 0.57 = 0.45, the weight of an empty box.