How many trips needed?

Question

If I can take two trips to the office within five minutes, how many minutes will $130$ trips take?

My attempt

$$\frac{130\text{ trips}}{2} = 65\text{ trips}$$

$$65 \cdot 5 = 325 \text{ minutes}$$

Answer 1

Assuming time per trip is for a round trip. At $2.5$ minutes per trip, time to take $130$ trips is $130 * 2.5$ Counting the interstitial $5$ minute intervals, add $(130-1)*5$

Answer 2

Hint: You can say you make $2/5$ of a trip to the office every minute. Now determine how many times this goes into $130$. To arrive at this idea, think about the units and cancellation when you divide/multiply.