Evaluate 5a+3 4b when a = b - 4and b = -2.
1 answer:
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Answer:
mean ≈ 25.45
Step-by-step explanation:
mean is calculated as
mean =
We require the sum for both classes
class A
mean = = 40 ( multiply both sides by 9 )
sum = 9 × 40 = 360
class B
mean = = 20 ( multiply both sides by 24
sum = 24 × 20 = 480
Total sum for both classes = 360 + 480 = 840 , then mean for both classes is
mean = ≈ 25.45 ( to 2 dec. places )