在口袋里放4个红球，6个蓝球．从中任意摸一个球，摸到蓝球的可能性是______，若想摸到红球的可能性是25%，口袋里必须再放______个蓝球．
（1）4÷（4+6）=
；3 5
（2）4÷25%-（4+6），
=16-10，
=6（个）；
答：任意摸一个球，摸到蓝球的可能性是
；若想摸到红球的可能性是25%，口袋里必须再放6个蓝球．3 5
故答案为：
，6．3 5
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| As soon as he finished his homework. Eric jumped onto his bicycle and rode off in the direction of the beach. While he was 1 along. He thought about the whales (鲸鱼). He hoped he would see them again today. After he got to the beach. Eric 2 his bicycle behind a bush so that no one could see it from the road. Then he ran down onto the sand. 3 it was only four in the afternoon,the sky was already growing dark. Eric frowned (皱眉). If it 4 he wouldn't be able to see the whales because they would stay in deeper water. He hurried along the beach 5 the rocks. They were the best place to watch the whales from because of their 6 . Before Eric reached the rocks he felt a drop of water on his head. "Oh, no!" he thought. "Now the whales will stay in the deep water and I won't be able to 7 them!" But just then he saw a large shape on the beach. It was a young whale! The whale had come too close to the shore (海岸) and got stuck (搁浅) on the 8 ! At first the whale didn't move at all and Eric thought it was 9 . Then he saw its tail move weakly. Eric turned and ran through the rain as fast as he could back to his bicycle. He had to get 10 ! Unless they got the whale back in the water soon,it would die and Eric couldn't let that happen. | ||||
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