A square has two parallel sides and four right angles.
I think
(Total)
3 : 6 : 8 = 17
(Times by 30 to get total then you times by each ratio/side)
90 : 180 : 240= 510cm
The option c is the answer because
2p=p (1.07)^x
2=1.07^x
Solve for x
X=log(2)÷log(1.07)
x=10 years the amount will be doubled after 10 years
But your option says the investment will (more) than double with (12) years
So it's correct