Mean of three numbers=Sum of three numbers3⇒10=Sum of three numbers3 [∵mean of three numbers=10, given]
Hence, sum of three numbers = 30
Mean of other four numbers =Sum of other four numbers4⇒12=Sum of other four numbers4 [∴mean of other four numbers=12,given]
Hence, sum of other four numbers = 48
∴ Mean of all the numbers =Sum of all the numbersTotal numbers=[Sum of first three numbers+Sum of other four numbers]7=30+487=787=11.14
Hence, mean of all the numbers is 11.14