c $Pollution ________ one of the longest challenges of the world. The air, water and soil ________ polluted. Air Pollution ________ the worst type ________________. It is caused by ________________ fetal diseases ________________ People ________ check/control ________ plant trees ________ use of vehicle etc. Love nature and get loved to make future.$ ...

English, 9 months ago

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there are two sections in IX class. the mean of the marks secured by 30 students of section a is 45, that of 50 students of sectiom b is 54. find the mean of all marks of students of the class​

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there are two sections in IX class. the mean of the marks secured by 30 students of section a is 45, that of 50 students of sectiom b is 54. find the mean of all marks of students of the class