I'm confused.Can someone tell me if I have done this correct.I'm trying to get the average using a weighted scale:

TOTAL GRADES: WEIGHT
90% ---------- 5%
100% ---------15%
95% --------- 15%
90% -----------5%
94.5% --------60%
I multiplied the total grade by the percent, then added the percent. But I get 109.20 as a final grade but I know that can be right...please help me. Thanks

90+100+95+90+94.5 = 469.5

469.5/5 = 93.9 = average grade without weighting.(weight of .20 or 20% for each)
now do it with weighting
90*.05 +100*.15+95*.15+90*.05 +94.5*.60= 90.9 with weighting

90*.05 +100*.15+95*.15+90*.05 +94.5*.60= 90.9 = 94.95

thanks for your help

To calculate the weighted average, you need to multiply each grade by its respective weight, sum those values, and divide by the total weight. Let's calculate it step by step:

1. Multiply each grade by its respective weight:
- 90% × 5% = 4.5
- 100% × 15% = 15
- 95% × 15% = 14.25
- 90% × 5% = 4.5
- 94.5% × 60% = 56.7

2. Add up the results:
4.5 + 15 + 14.25 + 4.5 + 56.7 = 95.95

3. Add up the weights:
5% + 15% + 15% + 5% + 60% = 100%

4. Calculate the weighted average:
95.95 ÷ 100% = 95.95%

Therefore, the correct weighted average for the given grades is 95.95%. The result you mentioned (109.20%) seems incorrect.