Algebra Pre-Algebra and Basic Algebra Math Forum

 November 2nd, 2015, 10:42 AM #1 Newbie   Joined: Nov 2015 From: Dorchester Posts: 1 Thanks: 0 Need help with this question please! I have been given the question: the mean on 4 numbers is 10 , the mean of a different set of 8 numbers is 7. What is the mean of all 12 numbers? Somebody please help me with this I don't understand it, thank you.  November 2nd, 2015, 11:10 AM #2 Global Moderator   Joined: Nov 2006 From: UTC -5 Posts: 16,046 Thanks: 938 Math Focus: Number theory, computational mathematics, combinatorics, FOM, symbolic logic, TCS, algorithms You know that (a1 + a2 + a3 + a4)/4 = 10 and that (b1 + b2 + ... + b8)/8 = 7. You're asked to find (a1 + a2 + a3+ a4 + b1 + ... + b8)/12. You can find a1 + a2 + a3 + a4 from the first average and b1 + b2 + ... + b8 from the second, and use that to find the final sum. Tags help or teach, mean or averages, question Thread Tools Show Printable Version Email this Page Display Modes Linear Mode Switch to Hybrid Mode Switch to Threaded Mode

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