I Live in Africa

Which 3-letter word can be inserted into all four lines above to form complete words?

P_ _ _ N T

D E _ _ _ S T

S T _ _ _

C _ _ _ E R

Figure out how many trailing zeroes are in 1000! 

If 

111 = 13

112 = 24

113 = 35

114 = 46

115 = 57

Then

116 = .....???

Can you solve it?

E + E + E = 15

E + C = 8

C + E + B = 10

B + C * J = ????