A container holds some water up to a height of 100 cm. When 2 identical plastic balls are put into the container, the water level rises by 18 cm. One plastic ball is then removed from the tank, replaced by one iron ball. The water level increases to 137 cm.
- Find the ratio of the volume of 1 plastic ball to 1 iron ball.
- If the base area of the container is 148 cm², find the difference in the volume between the iron ball and the plastic ball. Express your answer in cm³.
(a)
2 plastic balls → water level rises by 18 cm
Height of water per plastic ball
= 18 ÷ 2
= 9 cm
Height of water after one plastic ball is removed
= 100 + 18 - 9
= 109 cm
Height of water increased with 1 iron ball
= 137 - 109
= 28 cm
Ratio of the change in height of the plastic ball to the iron ball
= 9 : 28
(b)
Difference between the height of the iron ball and the plastic ball
= 28 - 9
= 19 cm
Difference between volume of the iron ball and the plastic ball
= 19 x 148
= 2812 cm
3 Answer(s): (a) 9 : 28; (b) 2812 cm
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