Average Practice Test 6

Average of 13 numbers = 68
∴ Total of 13 numbers = 13 × 68 = 884
Average of last 7 numbers = 70
∴ Total of last 7 numbers = 7 × 70 = 490
∴ Average of first 6 numbers = 884 – 490 = 394
∴Average of first 7 numbers = 63
∴ Total of first 7 numbers = 63 × 7 = 441
∴ 7th number = 441 – 394 = 47