Question

The mass of the bag and 18 balls is 2.7 kg. The mass of the same bag and 30 balls is 4.38 kg. Each ball has the same mass. What is the mass of the bag.?

Answer 1

Let the weight of bag be x kg and the weight of balls be y kg.

So in first case,

weight of bag + weight of 18 balls = 2.7 Kg

=> x + 18y = 2.7 kg

Second case,

weight of bag + weight of 30 balls = 4.38 kg

=> x + 30 y = 4.38 kg.


Now subtract first equation from the second

=> x + 30y - (x + 18y) = 4.38 - 2.7

=> x + 30y - x - 18y = 1.68

=> 12y = 1.68 kg

=> y = 1.68/12

=> y = 0.14 kg


So the weight of balls is 0.14 kg

Now we know that,

x + 18y = 2.7

=> x + 18(0.14) = 2.7

=> x + 2.52 = 2.7

=> x = 2.7 - 2.52

=> x = 0.18 Kg

So, the weight of bag is 0.18 kg


Hope it helps dear friend ☺️