The answer would be -4
Hope this helps
If you're taking trig, the "sum and difference formulas for trig functions" are basic facts that you'll need to learn and commit to memory. I'd suggest you look up these formulas on the net. You will likely immediately find listings for the sine, cosine and tangent.
The best estimate of the population mean is the sample mean
first calculate the sum of all samples:
32+24+14+34+26+27+31+16+18+26=248
then divide by the amount of samples to get the samples mean: 248/10=24.8 miles per gallon
