# Thread: Algebra problem dealing with lengths

1. ## Algebra problem dealing with lengths

If [ a ] = 5 cm , and [ b ] = 3a cm , find [ a + b ]

ANSWER=

2. $\displaystyle a = 5, b=3a= 3\times 5 = 15 \implies a+b = 5+15=\dots$

3. the answer is?

4. Take a guess, i dare you!