Q7 - Problem solving

The correct answer is B) u = s/27.

We are given s = 3t and t = 9u. To connect s directly to u, replace t in the first equation with 9u:

s = 3 × (9u) = 27u

Now divide both sides by 27 to isolate u:

u = s/27

The key is that s is 3 times t, and t is 9 times u, so s is 3 × 9 = 27 times u.

Dividing s = 27u by 27 gives u = s/27.