Answer:
x=2.4650
Step-by-step explanation:
I assume that you mean 
so let s use the ln() function

so x = ln(15)/ln(3)
x = 2.4650
1. D linear
2. A quadratic
3. B exponential
4. C rational
squash = cordial + water
400 ml = 50 ml + x ml
350 ml = x ml
Therefore, 350 ml are water.
350 ml / 400 ml = 0.875 = 
So the answer is 7 / 8