In a certain code language, HAIR is coded as 108, and NOSE is coded as 159. How will SKIN be coded in that language?

Let's find the positional place values of the letters in HAIR:
H=8,A=1,I=9,R=18
Sum of forward positional values: 8+1+9+18=36.
Notice that 36×3=108.

Let's see if this works for NOSE:

N=14,O=15,S=19,E=5
Sum of forward positional values: 14+15+19+5=53.
Notice that 53×3=159.

The logic is perfectly consistent:

Code=(Sum of forward positional values)×3
Now, let's find the value for SKIN:

S=19,K=11,I=9,N=14
Sum of these values: 19+11+9+14=53.
Multiplying by 3:

53×3=159