PrepTest 152 · Section 2 · Question 15

The Red-Paw Mystery

Biscuit trots inside with muddy paws. The mud is bright red. Marcus pulls out his magnifying glass. 'Aha! This red clay matches Grandpa's tomato garden. No other dirt in the neighborhood is this red. Biscuit dug up the tomatoes!' Grandpa is not pleased. Priya puts down her juice box. 'Grandpa, where does the red clay in your garden come from?' 'It's from a big clay layer under the hill,' Grandpa says. 'When it rains, that same clay washes down into the creek bed by the park.' Priya smiles. 'Biscuit went to the park this morning with Owen. He loves splashing in the creek.' Marcus lowers his magnifying glass. 'So the red clay could have come from the creek, too.' Biscuit wags his tail, innocent at last.

The clay on Biscuit's paws is bright red, and it matches the clay in Grandpa's garden. No other dirt in the neighborhood looks like it. So Biscuit probably dug in Grandpa's garden.

Which choice, if true, would most damage Marcus's argument?

The Case of the Purple Paint

In a fictional town, a fence is splashed with a rare purple paint. The only store that sells it is Paint Palace, and a customer bought some last week. 'Your Honor,' says the prosecutor, 'the paint matches. The customer did it.' Mr. Whitfield stands up slowly. 'This purple comes from a pigment mined in one quarry. That quarry also supplies a playground company, which painted the slide in the park right next to this fence, using the very same purple.' The prosecutor goes pale. The judge nods. 'So the paint match does not single out your customer anymore.' Another source with the same mark takes the bite out of the evidence.