ElectricPavlov

Yesssssss !

40% + 35 % = 80 %    so 20% are dated after 1980

20% is .20 in decimal form

.20 (1600) = 320 coins dated after 1980

j = 7d     given

     let 's' = papers taken from j

j - s   = 40         j= 40 + s

d + s = 40         d = 40 -s       sub these into the original equation

40+s = 7 (40-s)

s = 30 papers

7 cos 210 =  -6.06

7 sin 210 = -3.5i

Well let's say she flies for ONE hour.....then she should be 50.2 miles north and 1 hour's mph east

Bearing 68.9 is actually 21.1 in our usual coordinate 'plane'   (haha)

tan 21.1 = 50.2 / mph        mph = 130 mph

Volume_cyl  = pi r^2 h     Plug in the values given

8.5             = pi (r^2) h              lateral surface area = pi d h  = 3.5     so h =  3.5 / (pi2r)       sub into the equation

8.5 =  pi r^2 ( 3.5/ pi 2 r) 

8.5 =    3.5 r/2

17/3.5 = r   = 4.857 cm     

If you draw it out , you will find   AD = 13  cm              13 + 12 + 4 + 9 = 38 cm

[Ar] 4s²   3d¹⁰  4p⁵        for 35 electrons in bromine

Ca   is normally    1 s²    2s² 2p⁶   3s² 3p⁶   4s²       for 20 electrons

Argon   AR has 18 electrons  

            so   Ca could be    [Ar] 4s²          now remove one electron   to get Ca⁺  =     [ Ar] 4s¹

asin(0.1877) =~ 10.8186 ^o