Step 1: Underline key words
''Great bakers'' want to bake a cake to make a world record. They decided, the length of the cake should be three times it's breadth and with a perimeter 120 feet.
Step 2 :
Recognize/Define the variables : Length (l, say) and breadth (b, say)
Decipher the relation b/w variables : l = 3b …(1)
Also Perimeter = 120 feet.
Thus, 2( l + b) = 120
l + b = 60
Putting the value of l from (1) in the equation
3b + b = 60
4b = 60
b = 15
Thus, l=3×15=45
Therefore, the correct answer is 45.