Let total helicopters = h
L et total Tanks = t
Let total fighter jets = f
For every fighter jets there are four helicopters so the ratio of fighter jets to helicopters is 1:4

Target Question
What is the number of tanks in the sangalas Army?
find the value of t.

Statement 1
There are 15 tanks for every helicopter in Sangala's Army.
For every helicopter, there are 15 tanks
So the ratio of helicopter to tanks =1:15
If h=2, then t= 15*2=30
If h=3, then t= 15*3=45
t is a depend variable that changes with reference to the value of h and this cannot provide a definite Answer to the target question hence, statement 1 is INSUFFICIENT.

Statement 2
These are less than 200 tanks in Sangala's Army
i.e t<200 the value of t could be any value between 0 and 99 and this does not provide a definite answer to the target question, hence statement 2 is not SUFFICIENT.


Combining both statement together
h : t = 1: 15 ------eqn i
t < 200 -----eqn ii
from the question stem
f : h = 1 : 4
Therefore, f : h : t = 1 : 4 : (15*4) = 1 : 4 : 60
If f = 2 then f : h : t = 2 : (4*2) : 15*(4*2) = 2 : 8 : (15*8) = 2 : 8 : 120
the value of t is dependent on the value of h while the value of h is dependent on the value of 'f'.
since the exact value of f is unknown the target question cannot be answered with certainty, so both statement together are not SUFFICIENT..

$$Answer\ is\ Option\ E$$