There are 215 pieces of 4g and 9g balls in all.
The ratio of the weight of all 4g balls and all 9g balls is 3 : 4.
Find the number of 4g ball.
The ratio of the weight of all 4g balls and all 9g balls is 3 : 4.
Find the number of 4g ball.
Answer
The ratio of each number is (Weight of all 4g balls) / (weight of one 4g ball) : (weight of all 9g balls) / (weight of one 9g ball) = 3/4 : 4/9 = 27/36 : 16/36 = 27 : 16.
Since there are 215 balls, the number of 4g balls can be calculated by the proportional distribution and it is 215 balls × 27/(27+16) = 135 balls.
135 balls
Solution
The ratio of a weight of one piece of 4g ball 9g ball is 4g : 9g = 4 : 9.
Moreover, the ratio of the weight of all 4g balls and all 9g balls is 3 : 4.
Moreover, the ratio of the weight of all 4g balls and all 9g balls is 3 : 4.
The ratio of each number is (Weight of all 4g balls) / (weight of one 4g ball) : (weight of all 9g balls) / (weight of one 9g ball) = 3/4 : 4/9 = 27/36 : 16/36 = 27 : 16.
Since there are 215 balls, the number of 4g balls can be calculated by the proportional distribution and it is 215 balls × 27/(27+16) = 135 balls.
