Looks like the right approach... I did it without math.
(1) doesn't talk anything about # of years of experience - INSUFFICIENT
(2), the weighted average of 9.1 and 9.8 is 9.3 ... It allows for multiple values of 9.1 and 9.8 to make that 9.3 ... But the ratio will always be constant - SUFFICIENT
Can you explain this a bit more?? thx.
it's exactly what you did. its just terminology
weighted avg = (s1 +s2)/(N1+N2)
The combined sums are divided by the combined # of elements to produce a weighted outcome.
You tried your best and you failed miserably. The lesson is 'never try'. -Homer Simpson