#### Answer

Less than $150$ miles

#### Work Step by Step

Step 1. Based on the given conditions, the daily cost of the Basic Car Rental is $C_1=12+0.06x$, where $x$ is the miles driven.
Step 2. For the Acme Car Rental, the daily cost is $C_2=15+0.04x$
Step 3. Let $C_1 \lt C_2$. We have $12+0.06x \lt 15+0.04x$, which gives $0.02x \lt 3$ or $x\lt 150\ miles$
Step 4. Less than $150$ miles should be driven to make the daily cost of a Basic Rental a better deal than an Acme Rental.