Do You Have Any Maths Question? Kindly Bring It On

The explanation for this is much easier with a diagram.

Let G(z) = P(x is less than z).
Since the distribution is symmetric about the mean m, then G(m) = P(x < m) = 50%.

The statement "68 percent of the distribution lies within one standard deviation d of the mean" means that:
G(m+d) - G(m-d) = 68% = P(m-d<x<m+d)

So, we are looking for G(m+d)                                           which is also equal to P(x < m+d)

But P(x < m+d) = P(x < m) + P(m < x < m+d)
                         = P(x < m) + 0.5*[P(m-d < x < m+d)]       due to symmetric nature of distribution about the mean m
                         = G(m) + 0.5*(G(m+d) - G(m-d))               just substituting
                         = 50% + 0.5(68%)
                         = 50% + 34%
                         = 84% (Answer = D)

_{NOTE: there are several other ways of doing this.}

Eyohimself,

The agent must sell for $199,395(nearest $). 
Only Ann's gain is made on the initial cost price.
To the Agent the current cost price is 170270 + (0.11*170270) = $188,999.70
So, selling price is 188,999.70 + (0.055*188,99.70) = $199,394.68 ($199,395)

hi every one,

i'm happy to see o much going on on this thread.boy i ' have a lot of catching up to do.
eyohimself how is your prep.i'm sure you are in top shape.
i'm brewing some stuff.
Richyblacky
you are such a blessing on this thread.

There are 2 rooms. One has 3 light switches and the second one has three light bulbs. U can only enter the one with the light bulbs once. How do u deteremine which of the three light switches corresponds to three of the light bulbs in the second room

This forum and questions are too hot for me ,am logging out.

I love these guys.I which i also could be a mathematics guru as these guys up here.It's Cooooooooooooool!