The sides of a triangle are in the ratio $\frac{1}{3}:\frac{1}{4}:\frac{1}{5}$. If the semi-perimeter of the triangle is 47 cm, then what is the length of the longest side?

40 cm

The sides of a triangle are in the ratio $\frac{1}{3}:\frac{1}{4}:\frac{1}{5}$

The sides of a triangle are in the ratio 20:15:12

Assume the sides be 20x, 15x, 12x

Given, Semi Perimeter = (a+b+c)/2 = 47

47x/2 = 47

x= 2

The sides are  40, 30, 24

The correct answer is Option (2) → 40 cm