I would say 168 is the answer.
The answer is 6,072,825,688
Answer: 6 years
Step-by-step explanation:
Formula to calculate compound amount:
, where P= Principal , r=rate of interest, t= time
Given: P = £400, r = 3% = 0.03 , A= 475
Required equation: 

Taking log on both sides , we get

Hence, he needs to invest the money for 6 years to get atleast £475.
We first need to factorize (if possible) the denominators:
we can see that

as 2 and 5 are two numbers whose sum is 7 and product is 10.
Similarly, we can see that

as 2 and 3 are two numbers whose sum is 5 and product is 6.
Thus, the expression is:

.
Now to make the denominators equal, but to also keep them as small as possible, the common denominator must be (p+3)(p+2)(p+5).
Answer: (p+3)(p+2)(p+5).
The factors is 5,4,3,6,12