Answer:
See Below
Step-by-step explanation:
Thankfully, all the parts you need are given.
First, find the surface of one triangle
A = 1/2bh
A = 1/2(15)(9)
A = 1/2(135)
A = 67.5
Multiply by 4 to get the sum of all the sides.
67.5(4) = 270
Now find the surface area of one square
A = bh
A = (15)(15)
A = 225
multiply by 5 to get all 5 sides
225(5) = 1125
Add sums together
1125 + 270 = 1395
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.