Ihave no idea how to begin to figure this out. you in advance!

Index value at the end of the day will be $70400.

Step-by-step explanation:

Simple index of this stock market will be calculated as

Index = Sum of (Number of shares × Share value) of all companies

         = (5000×4.30 + 2000×3.20+ 8000×4.90)

         = 67000 + 6400 + 39200 = $67100

Now This index rises 4.9% over the course of day then index will be

Index after growth = 67100 + 67100×4.9%

                               = 67100 + 67100×.049 = 67100 + 3287.9

                               = 70387.9

We have to give the answer in nearest hundred so the index value will be $70400.