Class with boys and girls, each group's average weight given: average weight of the whole class

The same question, asked 2 times: 24 Jul 2023 S2*, 26 Sep 2024 S1. Every wording below, oldest first.

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Question 1
24 Jul 2023 S2
51 $In a class of 60 students, 20 are girls. The average weight of the boys in the class is 40 kg, while that of all the girls is 35 kg. What is the average weight (in kg) of the entire class (correct to two decimal places)?$
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Question 2
26 Sep 2024 S1
52 $In a class of 150 students (boys and girls only), the girls are 60. The average weight of boys is 52 kg and that of girls is 48 kg. What is the average weight (in kg) of the whole class?$
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Question 1