let's convert firstly the mixed fractions to improper fractions and then add up.
![\bf \stackrel{mixed}{2\frac{3}{8}}\implies \cfrac{2\cdot 8+3}{8}\implies \stackrel{improper}{\cfrac{19}{8}}~\hfill \stackrel{mixed}{1\frac{1}{4}}\implies \cfrac{1\cdot 4+1}{4}\implies \stackrel{improper}{\cfrac{5}{4}} \\\\\\ \stackrel{mixed}{2\frac{7}{8}}\implies \cfrac{2\cdot 8+7}{8}\implies \stackrel{improper}{\cfrac{23}{8}} \\\\[-0.35em] ~\dotfill](https://tex.z-dn.net/?f=%5Cbf%20%5Cstackrel%7Bmixed%7D%7B2%5Cfrac%7B3%7D%7B8%7D%7D%5Cimplies%20%5Ccfrac%7B2%5Ccdot%208%2B3%7D%7B8%7D%5Cimplies%20%5Cstackrel%7Bimproper%7D%7B%5Ccfrac%7B19%7D%7B8%7D%7D~%5Chfill%20%5Cstackrel%7Bmixed%7D%7B1%5Cfrac%7B1%7D%7B4%7D%7D%5Cimplies%20%5Ccfrac%7B1%5Ccdot%204%2B1%7D%7B4%7D%5Cimplies%20%5Cstackrel%7Bimproper%7D%7B%5Ccfrac%7B5%7D%7B4%7D%7D%20%5C%5C%5C%5C%5C%5C%20%5Cstackrel%7Bmixed%7D%7B2%5Cfrac%7B7%7D%7B8%7D%7D%5Cimplies%20%5Ccfrac%7B2%5Ccdot%208%2B7%7D%7B8%7D%5Cimplies%20%5Cstackrel%7Bimproper%7D%7B%5Ccfrac%7B23%7D%7B8%7D%7D%20%5C%5C%5C%5C%5B-0.35em%5D%20~%5Cdotfill)

Answer: 35.5
Step-by-step explanation: The mean of a data set is equal to the sum of the set of numbers divided by how many numbers are in the set.
So to find the mean of the data set shown here, let's begin by adding the numbers.
31 + 29 + 33 + 37 + 33 + 38 + 43 + 40 = 284
284 will be divided by how many numbers are in the data set which is 8 so we have to divide 284 by 8.
248 ÷ 8 = 35.5
Therefore, the mean of the data set shown here is 35.5.
Answer:
Surface area = 505cm²
Step-by-step explanation:
Surface area of the triangular prism. = 2B + ph
B is the base area
p is the perimeter of the triangle
h is the height of the triangle
Base area = 1/2 * base * height
Base area = 1/2 * 18 * 40
Base area = 9 * 40
Base area = 360cm²
Perimeter of the triangle = 41 + 41 + 18
Perimeter of the triangle = 100cm
height of the prism = 45cm
Surface area = 360 + 100 + 45
Surface area = 505cm²